Tag Archives: astronomers

Astronomers discover colorful ‘glory’ in the atmosphere of WASP-76b

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Using data from ESA's Extraterrestrial Planet Characterization Satellite (CHEOPS) and several other ESA and NASA missions, astronomers detected signs of extraterrestrial planets. Rainbow-like “glory effect” In the atmosphere of super-hot Jupiter WASP-76b. This effect occurs when light is reflected from a cloud composed of a completely homogeneous but so far unknown material. This “glory effect” is common on Earth, but it has only been discovered once on another planet, Venus. If confirmed, this first extrasolar glory would reveal more about the nature of this puzzling exoplanet and hold exciting lessons about how to better understand strange, distant worlds.

Artist's impression of WASP-76b's atmospheric rainbow-like “glory effect.” Image credit: ESA.

WASP-76b is the superhot planet Jupiter located 640 light-years away in the constellation Pisces.

First discovered in 2016, this exoplanet orbits the F-type star WASP-76 once every 1.8 days.

WASP-76b is tidally locked to its star. It takes about the same amount of time to rotate around its axis as it does to orbit its parent star.

On the day side, the planet receives thousands of times more radiation from its star than Earth receives from the Sun.

Temperatures on the dayside can exceed 2,400 degrees Celsius (4,352 degrees Fahrenheit), high enough to vaporize metals. However, nighttime temperatures are much cooler at 1,316 degrees Celsius (2,400 degrees Fahrenheit).

Here, the elements that form Earth's rocks melt and evaporate, condensing on the slightly cooler night side and creating iron clouds that drip rain of molten iron.

But astronomers have been puzzled by the apparent asymmetry, or oddity, of WASP-76b's “limbs,” the outermost regions seen as it passes in front of its host star.

“WASP-76b is being 'inflated' by the intense radiation from its star,” said Dr. Monica Rendl, an astronomer at the University of Geneva.

“That means it's 10% less massive than our cousin Jupiter, but almost twice the size.”

“The important thing to keep in mind is the incredible scale of what we are witnessing,” says ESA astronomer Dr Matthew Standing.

“WASP-76b is a very hot gas giant planet hundreds of light years away, likely raining molten iron. Despite the chaos, we detected potential signs of glory. It seems like it's an incredibly weak signal.''

In this study, the authors analyzed data from a variety of ESA and NASA missions, including CHEOPS, TESS, Hubble, and Spitzer.

CHEOPS intensively monitored WASP-76b as it passed in front of and around a Sun-like star. After making her 23 observations over three years, the data showed a surprising increase in the amount of light emanating from the planet's eastern “terminator,” the boundary where night and day meet. .

This allowed astronomers to disentangle the signal and constrain its origin.

“This is the first time that such a sudden change in the brightness of an exoplanet, its 'phase curve', has been detected,” said Dr. Olivier Demanjon, an astronomer at the Spanish Institute of Astronomical Sciences in Portugal.

“This discovery led to the hypothesis that this unexpected glow may be caused by a strong, locally anisotropic (direction-dependent) reflection, or glow effect.”

“Never before have we seen such colorful concentric rings on an extrasolar object,” said Dr Thomas Wilson, an astronomer at the University of Warwick.

“Therefore, if future studies confirm the glory of this first exoplanet, WASP-76b will be a truly unique object, providing insight into the atmospheres of distant exoplanets and how habitable they may be. It’s a beautiful tool for understanding.”

Confirmation of the glory effect means that the cloud, which is made up of perfectly spherical droplets, has lasted at least three years or is constantly replenished.

For these clouds to persist, the atmospheric temperature must also remain stable over time. This is an interesting and detailed insight into what's going on with WASP-76b.

Importantly, being able to detect such subtle wonders at great distances will teach scientists and engineers how to detect other less visible but important phenomena. For example, sunlight reflecting off liquid lakes and oceans is a requirement for habitability.

“More evidence is needed to say conclusively that this interesting 'extra light' is a rare glory,” said Dr Teresa Luftinger, project scientist for ESA's upcoming Ariel mission.

“Follow-up observations by the NIRSPEC instrument aboard the NASA/ESA/CSA James Webb Space Telescope could do just that. Or perhaps ESA’s upcoming Ariel mission will prove its existence.” We may even discover brighter colors shining from other exoplanets.”

a paper The survey results were published in a magazine astronomy and astrophysics.

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ODS demansion other. 2024. Asymmetry in the atmosphere of superhot Jupiter WASP-76b. A&A 684, A27; doi: 10.1051/0004-6361/202348270

Source: www.sci.news

Astronomers Uncover Two Ancient Substructures within the Milky Way

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The newly identified structures, called Shakti and Shiva, are between 12 billion and 1 billion years old, making them so old that they are even older than the spiral arms and oldest parts of the present-day Milky Way galaxy's disk. may have been formed before.

This image shows the location and distribution of Shakti (yellow) and Shiva (blue) stars throughout the Milky Way. Image credit: ESA / Gaia / DPAC / K. Malhan.

“What's really amazing is that we can detect these ancient structures at all,” said Dr. Kati Malhan, an astronomer at the Max Planck Institute for Astronomy.

“The Milky Way has changed so much since these stars were born that we didn't expect to be able to see them so clearly as a group. But the unprecedented data obtained from ESA's Gaia satellite Thanks to you, this is possible.”

Using Gaia observations, Dr. Mulhan and Dr. Hans-Walter Rix of the Max Planck Institute for Astronomy were able to determine the orbits of individual stars in the Milky Way, as well as their content and composition.

“When we visualized the orbits of all these stars, we found that two new structures stood out from the rest among stars of certain chemical compositions. We named them Shakti and Shiva. '' said Cati.

Each stream contains the mass of about 10 million suns, and the stars, all 12 to 13 billion years old, have similar compositions and move in very similar orbits.

The way they are distributed suggests that they may have formed as separate pieces that merged with the Milky Way early in their lives.

Shakti and Shiva both lie towards the center of the Milky Way.

Gaia explored this part of the Milky Way in 2022 using a type of galactic archaeology. This indicates that this region is filled with the oldest stars in the entire galaxy, all of which were born before the Milky Way disk was properly formed.

“The stars there are so old that they lack many of the heavy metal elements that were created later in the life of the universe,” Dr. Ricks says.

“Because the stars at the center of our galaxy are metal-poor, we named this region the 'poor old heart' of the Milky Way.”

“Until now, we were only aware of very early fragments that came together to form the ancient core of the Milky Way.”

“In Shakti and Shiva we see the first works that appear to be relatively ancient but are located further out.”

“These represent the first steps in the galaxy's growth towards its current size.”

The two streams are very similar, but not identical. The star Shakti orbits a little farther from the center of the Milky Way galaxy and has a more circular orbit than the star Shiva.

Fittingly, these streams are named after the divine couple in Hindu philosophy who come together to create the universe.

About 12 billion years ago, the Milky Way was very different from the orderly spiral we see today.

They believe that our galaxy was formed by the merging of multiple long, irregular filaments of gas and dust that all formed stars and intertwined, giving rise to the galaxy as we know it. It is being

Shaki and Shiva appear to be two of these components, and future Gaia data releases may reveal more.

The authors also created a dynamic map of other known components that play a role in galaxy formation and were discovered using Gaia data.

These include Gaia-Sausage-Enceladus, LMS1/Wukong, Arjuna/Sequoia/I'itoi, and Pontus.

These groups of stars all form part of the Milky Way's complex genealogy that Gaia has been working to build over the past decade.

Dr Timo Prusti, ESA astronomer and Gaia project scientist, said: “Learning more about the early life of the Milky Way is one of Gaia's goals, and we are well on our way to achieving it.”

“To understand how our galaxy formed and evolved, we need to pinpoint subtle but crucial differences between the Milky Way's stars.”

“This requires incredibly accurate data, and now, thanks to Gaia, we have that data.”

“As we discover surprising parts of our galaxy, such as the Shiva and Shakti rivers, we are filling in the gaps and painting a complete picture not just of our current homeland, but of the earliest history of the universe.”

of study Published in astrophysical journal.

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Catty Mulhan & Hans-Walter Ricks. 2024. Shiva and Shakti: A fragment of a primordial galaxy presumed to be inside the Milky Way. APJ 964, 104; doi: 10.3847/1538-4357/ad1885

Source: www.sci.news

Astronomers find previously unknown quasar in far-off galaxy cluster

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Astronomers used NASA’s Chandra X-ray Observatory and NSF’s Carl G. Jansky Very Large Array (VLA) to locate H1821+643, the closest quasar hosted by a galaxy cluster, about 3.4 billion light years away. The quasar was found to be more powerful than many supermassive black holes in other galaxy clusters.

This composite image shows quasar H1821+643.Image credit: NASA / CXC / University of Nottingham / Russell other. / NSF / NRAO / VLA / SAO / N. Walk.

Quasars are a rare and extreme class of supermassive black holes that violently pull matter inward, producing intense radiation and sometimes powerful jets.

This quasar, known as H1821+643, is about 3.4 billion light-years from Earth and contains a black hole with a mass of 4 billion solar masses.

Most growing supermassive black holes pull matter in at a slower rate than quasars.

Astronomers have been studying the effects of these more common black holes by observing black holes at the centers of galaxy clusters.

Periodic explosions from such black holes prevent the massive amount of superheated gas embedded in the black hole from cooling down, increasing the number of stars forming in its host galaxy and the fuel pouring toward the black hole. limit the amount of

Little is known about how much influence quasars within galaxy clusters have on their surroundings.

“Our research shows that quasars appear to have given up much of the control imposed by slower-growing black holes. The appetite of black holes is unmatched in their influence,” Nottingham said. University astronomer Dr Helen Russell said.

To reach this conclusion, Russell and his colleagues used Chandra to study the hot gas surrounding H1821+643 and its host galaxy.

But the bright X-rays from quasars have made it difficult to study the weaker X-rays from hot gases.

“To reveal the effects of a black hole, we had to carefully remove the X-ray glare. Then we found that it actually had little effect on its surroundings,” says Harvard University. said Dr. Paul Nalsen, an astronomer at the Smithsonian Center for Astrophysics.

Using Chandra, astronomers discovered that the density of gas near the black hole at the center of a galaxy is much higher than in more distant regions, and the temperature of the gas is much cooler.

Researchers believe that when there is little or no energy input (usually from an explosion from a black hole), hot gas behaves this way to prevent it from cooling and flowing toward the center of the cluster. Expect.

“The supermassive black hole generates far less heat than other black holes at the center of galaxy clusters. This allows the hot gas to cool rapidly and form new stars, which fuel the black hole. It also acts as a source,” said Dr Lucy Crews, an astronomer at the Open University.

The researchers determined that the equivalent of about 3,000 solar masses per year of hot gas has cooled to the point where it is no longer visible in X-rays.

This rapid cooling easily supplies enough material for the 120 solar masses of new stars observed to form each year within the host galaxy and the 40 solar masses consumed by black holes each year. be able to.

The scientists also investigated the possibility that radiation from quasars directly causes cooling of the cluster's hot gases.

This involves photons of light from the quasar colliding with electrons in the hot gas, increasing the energy of the photons and causing the electrons to lose energy and cool down.

This study showed that this type of cooling is probably occurring within the cluster containing H1821+643, but is too weak to explain the large amount of gas cooling seen.

Dr Thomas Braben, an astronomer at the University of Nottingham, said: “This black hole may not be producing enough because it isn't pumping any heat into its surroundings, but the current situation won't last forever.'' ” he said.

“Ultimately, the rapid uptake of fuel by the black hole should increase the jet's power and strongly heat the gas.”

“After that, the growth of the black hole and its galaxy should slow down significantly.”

team's paper will be published in Royal Astronomical Society Monthly Notices.

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HR Russell other. 2024. Cooling flow around low-redshift quasar H1821+643. MNRAS, in press. arXiv: 2401.03022

Source: www.sci.news

Aurora-like radio emissions detected above sunspots by solar astronomers

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Astronomers using the Karl G. Jansky Very Large Array have observed long-lasting aurora-like radio bursts above sunspots. This discovery could help us better understand the behavior of our own star, as well as distant stars that emit similar radio emissions.

excellent other. We discovered radio bursts above sunspots that are similar to the radio emissions from the aurora borealis on Earth. The pink and purple stripes in this figure represent radio wave radiation, with high frequency radio signals near the sunspots, pink being high frequency and purple being low frequency radio signals. The thin lines represent the magnetic field lines above the sunspot. Sunspots are dark areas at the bottom of the sun. Image credit: Sijie Yu, New Jersey Institute of Technology.

“This sunspot's radio emission represents the first detection of its kind,” said Dr. Shijie Yu, an astronomer at the New Jersey Institute of Technology.

“Such radio bursts were detected about 40,000 kilometers (25,000 miles) above sunspots (relatively cool, dark, magnetically active regions of the Sun) that had previously been observed only on planets and other stars. It was done.”

On other planets like Earth, Jupiter, and Saturn, auroras sparkle in the night sky when solar particles get caught up in the planet's magnetic field and are pulled toward the poles where the magnetic field lines converge.

As the particles accelerate toward the poles, they generate powerful radio emissions at frequencies around a few hundred kilohertz that collide with atoms in the atmosphere and emit light as auroras.

The research team's analysis shows that radio bursts on sunspots likely occur in a similar way, when high-energy electrons are captured and accelerated by magnetic fields converging on sunspots. It suggests.

However, unlike Earth's aurora borealis, the radio bursts from sunspots occur at much higher frequencies, from hundreds of thousands of kilohertz to approximately one million kilohertz.

“This is a direct result of the sunspot's magnetic field being thousands of times stronger than Earth's magnetic field,” Yu says.

Similar radio emissions have been previously observed from several types of low-mass stars.

This discovery raises the possibility that auroral-like radio emissions originate from large spots on these stars, in addition to previously proposed polar auroras.

“This discovery excites us as it challenges existing concepts of solar radio phenomena and opens new avenues for exploring magnetic activity both in the Sun and in distant star systems. ” said Dr. Yu.

“NASA's ever-growing heliophysics fleet is well suited to continue investigating the source regions of these radio bursts,” said NASA Goddard Space Flight Center heliophysicist and solar radio researcher. said Dr. Nachimthuk Gopalswamy.

“For example, the Solar Dynamics Observatory continuously monitors the active regions of the Sun, which could be causing this phenomenon.”

In the meantime, the authors plan to review other solar radio bursts to see if any resemble the aurora-like radio bursts they discovered.

“We aim to determine whether some previously recorded solar outbursts may be examples of this newly identified emission,” Dr. Yu said.

of findings appear in the diary natural astronomy.

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S.Yu other. 2024. Long-lasting aurora-like radio emission detected over a sunspot. Nat Astron 8, 50-59; doi: 10.1038/s41550-023-02122-6

Source: www.sci.news

Astronomers produce the most extensive map of quasars in the universe ever recorded

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of new mapThis quasar, called Quaia, contains about 1,295,502 quasars from across the visible universe and could help astronomers better understand the properties of dark matter.

story fisher other. This is an all-sky quasar catalog that samples the largest comoving volume of any existing spectroscopic quasar sample.Image credit: Story Fisher other., doi: 10.3847/1538-4357/ad1328.

Quasars are powered by supermassive black holes at the centers of galaxies and can be hundreds of times brighter than entire galaxies.

When the black hole's gravity kicks up nearby gas, the process creates a very bright disk, and sometimes a jet of light, that can be observed with telescopes.

The galaxies that quasars live in are hidden in huge clouds of invisible dark matter.

The distribution of dark matter gives insight into how much dark matter is present in the universe and how strongly clustered it is.

Astronomers compare these measurements across cosmic time to test current models about the composition and evolution of the universe.

Quasars are so bright that astronomers use them to map dark matter in the distant universe and fill in a timeline of how the universe evolved.

For example, scientists are already comparing the new quasar map to the Cosmic Microwave Background, the oldest snapshot of light in the universe.

As this light travels to us, it is bent by an intervening web of dark matter (the same web drawn by quasars), and by comparing the two, scientists can determine how matter changes over time. You can measure how strongly it clumps together.

“The new quasar catalog differs from all previous catalogs in that it provides the largest volumetric three-dimensional map in the history of the universe,” said David, an astronomer at the Center for Computational Astrophysics at the Flatiron Institute in New York.・Professor Hogg said. University.

“This is not the catalog with the most quasars or the highest quality quasar measurements, but it is the catalog with the largest total volume of the universe mapped.”

Professor Hogg and his colleagues constructed the Quasar map using data from the third data release of ESA's Gaia mission, which includes 6.6 million quasar candidates, as well as data from NASA's Wide-field Infrared Explorer and Sloan Digital Sky Survey. did.

By combining the datasets, contaminants such as stars and galaxies were removed from Gaia's original dataset and the distance to the quasar was determined more precisely.

“We were able to measure how matter clustered in the early universe with as much precision as those from major international research projects. Data as a 'bonus' from the Milky Way This is quite remarkable considering that we got . We are focusing on the Gaia project,” said Dr. Kate Storey-Fisher, a postdoctoral researcher at the International Physics Center Donostia.

“It's very exciting to see this catalog spurring so much new science.”

“Researchers around the world use quasar maps to measure everything from variations in the initial density that seeds the cosmic web, to the distribution of voids in the universe, to the movement of our solar system through space. ”

Astronomers have created a map showing where dust, stars, and other nuisances are expected to obstruct the view of certain quasars. This is important in interpreting quasar maps.

“This catalog of quasars is a great example of how productive astronomy projects can be,” Professor Hogg said.

“Gaia was designed to measure stars in our galaxy, but it also discovered millions of quasars, giving us a map of the entire universe.”

of result will appear in astrophysical journal.

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Kate Story Fisher other. 2024. Quair, Gaia-unWISE quasar catalog: all-sky spectroscopic quasar samples. APJ 964, 69; doi: 10.3847/1538-4357/ad1328

Source: www.sci.news

Astronomers discover floating crystals preventing cooling in high-mass white dwarf stars

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Astronomers have proposed a new theory to explain why a mysterious population of white dwarfs has stopped cooling for at least 8 billion years.

This diagram shows a white dwarf and the moon. Image credit: Giuseppe Parisi.

White dwarfs are the remains of stars without a nuclear energy source that gradually cool over billions of years, eventually freezing from the inside out to a solid state.

Recently, it was discovered that a population of frozen white dwarfs maintains a constant brightness for a period comparable to the age of the universe, indicating the existence of an unknown, powerful energy source that inhibits cooling.

“We find that the classical picture that all white dwarfs are dead stars is incomplete,” said astronomer Dr Simon Bruin from the University of Victoria.

“To stop these white dwarfs from cooling, we need some way to generate additional energy.”

“We didn’t know how this happened, but now we have an explanation for this phenomenon.”

The researchers say that in some white dwarfs, the dense plasma inside them doesn’t just freeze from the inside out.

Instead, the solid crystals that form when frozen tend to float because they are less dense than the liquid.

As the crystals float upwards, the heavier liquid moves downwards.

As heavy material is transported toward the star’s center, gravitational energy is released, and this energy is enough to interrupt the star’s cooling process for billions of years.

Dr Antoine Bedard, an astronomer at the University of Warwick, said: “This is the first time this transport mechanism has been observed in any type of star, and it’s very interesting because it’s not every day that a completely new astrophysical phenomenon is discovered.”

“We don’t know why this happens in some stars and not others, but it’s probably due to the star’s composition.”

“Some white dwarfs are formed by the merger of two different stars,” Dr Bruin said.

“When these stars collide to form white dwarfs, the star’s composition changes, allowing the formation of floating crystals.”

White dwarfs are routinely used as an indicator of age, and the cooler a white dwarf is, the older it is considered to be.

However, the extra delay in cooling seen in some white dwarfs means that some stars at certain temperatures may be billions of years older than previously thought.

“This new discovery will not only require a revision of astronomy textbooks, but will also require a reexamination of the processes astronomers use to determine the age of stellar populations,” Dr. Blouin said.

of the team paper Published in today’s diary Nature.

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A. Bedard other. Buoyant crystals stop the white dwarf from cooling. Nature, published online March 6, 2024. doi: 10.1038/s41586-024-07102-y

Source: www.sci.news

Astronomers discover the heaviest supermassive black hole pair ever measured

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Astronomers are gemini north telescope measured a binary supermassive black hole located within the elliptical galaxy B2 0402+379.

Artist's impression of the supermassive black hole binary in elliptical galaxy B2 0402+379. Image credit: NOIRLab / NSF / AURA / J. daSilva / M. Zamani.

The pair of compact objects at the center of B2 0402+379 are the only supermassive black hole binaries ever resolved in enough detail that both objects can be seen separately.

It holds the record for the smallest distance ever directly measured – just 24 light years.

While this close separation portends a strong merger, further research reveals that the pair has been stuck at this distance for more than 3 billion years, raising questions. What is the holdup?

To better understand the dynamics of this system and its stalled merger, Stanford University professor Roger Romani and his colleagues turned to archival data from Gemini North. Gemini multi-object spectrometer (GMOS) This allowed them to determine the speed of stars near the black hole.

“The excellent sensitivity of GMOS allowed us to map the increasing velocity of stars as they approach the center of the galaxy. This allowed us to estimate the total mass of black holes present there.” Professor Romani said.

The authors estimate that the binary star's mass is a whopping 28 billion times that of the Sun, making the pair the most massive binary black hole ever measured.

This measurement not only provides valuable background on the formation of binary systems and the history of their host galaxies, but also confirms the long-held belief that the mass of supermassive binary black holes plays a key role in preventing potential mergers. This supports the theory.

“The data archive provided by the International Gemini Observatory holds a goldmine of untapped scientific discoveries,” said Dr. Martin Still, NSF program director for the International Gemini Observatory.

“Measuring the mass of this extreme supermassive binary black hole is an awe-inspiring example of the potential impact of new research exploring its rich archive.”

Understanding how this binary formed can help predict if and when it will merge. Also, some clues indicate that the pair formed through multiple galaxy mergers.

First, B2 0402+379 is a “fossil cluster,” meaning it is the result of an entire galaxy cluster's worth of stars and gas merging into a single giant galaxy.

Additionally, the presence of two supermassive black holes, coupled with their large combined mass, suggests that they resulted from the merger of multiple smaller black holes from multiple galaxies.

After galaxies merge, supermassive black holes do not collide head-on. Instead, they start slingshotting each other as they settle into a certain trajectory.

Each time a black hole passes, energy is transferred from it to the surrounding stars.

Losing their energy, the pair are dragged together, and gravitational radiation takes over, merging them just a few light years away.

This process has been observed directly in pairs of stellar-mass black holes, first documented by the detection of gravitational waves in 2015, but has never been observed in binaries of supermassive black holes.

With new knowledge about the system's extremely large mass, astronomers concluded that it would take a very large number of stars to slow down the binary enough to make its orbits so close together. .

In the process, the black hole seems to have blown away almost all the material around it, depleting the galaxy's center of stars and gas.

The merger of the two companies stalled in the final stages, as there was nothing left to further slow the companies' trajectory.

“Galaxies with lighter black hole pairs usually seem to have enough stars and mass to quickly merge the two,” Professor Romani said.

“The pair is so massive that we needed a lot of stars and gas to get the job done. But binaries scour the galaxy for such material, causing it to stagnate, making it impossible for our research to do so.” has been made accessible.”

It remains to be determined whether the pair will overcome stasis and eventually merge on a timescale of millions of years, or remain in orbit forever in limbo.

If they merged, the resulting gravitational waves would be 100 million times more powerful than those produced by the merger of stellar-mass black holes.

The pair could potentially conquer that final distance via another galactic merger. In that case, additional material, or potentially a third black hole, could be injected into the galaxy, slowing the pair's orbits enough for a merger.

However, given that B2 0402+379 is a fossil cluster, further galaxy mergers are unlikely.

“We're looking forward to tracking the core of B2 0402+379 to find out how much gas is present,” said Tirth Surti, an undergraduate at Stanford University.

“This should give us more insight into whether supermassive black holes may eventually merge or remain stuck as binaries.”

of result will appear in astrophysical journal.

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Tirth Surti other. 2024. Central kinematics and black hole mass of 4C+37.11. APJ 960, 110; doi: 10.3847/1538-4357/ad14fa

Source: www.sci.news

Radcliffe waves found to exhibit oscillations by astronomers

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Our Sun is within 300 parsecs (about 1,000 light-years) of a 2,700-parsec (about 9,000 light-years) long sinusoidal dense gas cloud known as the Radcliffe wave. The wavy shape of this structure was discovered using 3D dust mapping, but initial kinematic investigations of its oscillatory motion were inconclusive. Radcliffe waves oscillate in the plane of the Milky Way galaxy, radiating away from the galaxy's center, according to a new study.

Radcliffe waves next to the sun (yellow dot) in a cartoon model of the Milky Way. The blue dots are a group of baby stars.The white line is the theoretical model by Konietzka other. It describes the current shape and movement of the wave. The magenta and green lines show how the waves will move in the future. Image credit: Ralf Konietzka / Alyssa Goodman / Worldwide Telescope.

“By using the movement of baby stars born in gas clouds along Radcliffe waves, we can track the movement of the natal gas and show that the Radcliffe waves are actually rippling,” says Ralph.・Dr. Konietzka said. He is a student at Harvard University and the Smithsonian Center for Astrophysics.

In 2018, astronomers mapped the 3D location of a stellar nursery in the sun's galactic neighborhood.

By combining new data, ESA's Gaia Mission Using a data-intensive “3D dust mapping” technique, they noticed an emerging pattern, leading to the discovery of the 2020 Radcliffe wave.

“This is the largest coherent structure that we know of, and it's in our immediate vicinity,” said Dr. Katherine Zucker, an astronomer at the Harvard University & Smithsonian Center for Astrophysics.

“It's been there all along. We just didn't know it because we weren't able to build high-resolution models in 3D to show the distribution of gas clouds near the Sun.”

Although the 3D dust map clearly showed that Radcliffe waves were present, sufficient measurements were not available at the time to confirm whether the waves were moving.

But in 2022, astronomers used a new release of Gaia data to assign 3D motion to young star clusters in Radcliffe waves.

By understanding the location and movement of the clusters, they were able to confirm that the entire Radcliffe wave was indeed undulating, moving like what physicists call a “traveling wave.”

“Traveling waves are the same phenomenon you see in sports stadiums, where people take turns standing and sitting to do waves,” Konietzka said.

“Similarly, star clusters along Radcliffe waves move up and down, creating patterns that travel through the galaxy's backyard.”

“In the same way that fans in a stadium are pulled back into their seats by Earth's gravity, Radcliffe waves are oscillated by the Milky Way's gravity.”

No one yet knows what causes Radcliffe waves or why they behave the way they do.

“Now we can test all the different theories about why the waves formed in the first place,” Dr. Zucker said.

“Those theories range from the explosion of a giant star called a supernova to disturbances outside the galaxy, such as a dwarf satellite galaxy colliding with the Milky Way,” Konietzka added.

“It turns out we don't need significant dark matter to explain the motion we observe.”

“The gravity of ordinary matter is enough to move waves.”

Furthermore, the discovery of this oscillation has raised new questions about the predominance of these waves in both the Milky Way and other galaxies.

Radcliffe waves appear to form the backbone of the Milky Way's closest spiral arms, so the ripples in these waves may be due to the oscillations of galactic spiral arms in general, making galaxies even more dynamic than previously thought. It may suggest that you are doing something.

“The question is: What causes the displacement that causes the ripples that we see?” said Professor Alyssa Goodman, an astronomer at Harvard University and the Smithsonian Center for Astrophysics.

“And does it happen throughout the galaxy? In every galaxy? Does it happen sometimes? Does it happen all the time?

of result appear in the diary Nature.

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R. Konietzka other. Radcliffe waves are oscillating. Nature, published online on February 20, 2024. doi: 10.1038/s41586-024-07127-3

Source: www.sci.news

New Moons Found Around Uranus and Neptune by Astronomers

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The three newly discovered moons (S/2023 U1, S/2002 N5, and S/2021 N1) are the faintest ever discovered around Uranus and Neptune using ground-based telescopes.

Discovery image of Uranus’ moon S/2023 U1 using the Magellan Telescope on November 4, 2023. Image credit: Scott Sheppard.

The new Uranian moon, tentatively named S/2023 U1, was first discovered by astronomers at the Carnegie Institution for Science on November 4, 2023. Scott Sheppard using the Magellan Telescope at the Las Campanas Observatory.

At just 8 km (5 miles), it is probably the smallest of Uranus’ moons. It takes 680 days to circumnavigate the ice giant.

S/2023 U1 will eventually be named after a character from a Shakespeare play, following Uranus’ outer moon naming conventions.

This discovery brings the total number of moons on this giant icy planet to 28.

Dr. Sheppard also used the Magellan telescope to discover S/2002 N5, the brighter of two newly discovered Neptune moons.

The moon’s diameter is about 23 km (14.3 miles), and it takes almost nine years to circumnavigate the ice giant.

The dimmer moons of Neptune were discovered by Dr. Sheppard and his colleagues using the Subaru telescope.

The star, named S/2021 N1, is about 14 km (8.7 miles) in diameter and has an orbital period of almost 27 years.

S/2002 N5 and S/2021 N1 were both first seen in September 2021.

Both have enduring names based on the 50 Nereid sea goddesses from Greek mythology.

“The orbit around Neptune of S/2002 N5 is determined using observations from 2021, 2022, and 2023, indicating that it was discovered near Neptune in 2003, but is still orbiting the planet. “We were able to trace it back to an object that was lost before it was confirmed,” Sheppard said.

S/2023 U1, S/2002 N5, and S/2021 N1 have far-flung, eccentric, and inclined orbits that occurred when Uranus and Neptune were formed from rings of dust and debris surrounding them, or it suggests that they were captured by the gravity of these planets shortly after our sun is in its infancy.

All giant planets in our solar system, regardless of their size or formation process, have a similar composition of outer moons.

“Even Uranus, which is tilted sideways, has a moon population similar to other giant planets orbiting the sun,” Dr. Sheppard said.

“And Neptune, which likely captured the distant Kuiper Belt object Triton, an event that could disrupt its lunar system, has an outer moon that looks similar to its neighbors. “

This new moon also indicates the existence of a dynamic orbital group of outer moons around Uranus and Neptune, similar to those seen around Jupiter and Saturn.

At Uranus, S/2023 U1 has an orbit similar to Caliban and Stefano.

At Neptune, S/2021 N1 has an orbit similar to Psamate and Neso, and S/2002 N5 has an orbit similar to Thao and Laomedeia.

These groupings suggest that the once larger parent moon was shattered, perhaps by a past collision with a comet or asteroid, leaving shattered debris in an orbit similar to the original larger moon. There is.

Many small lunar fragments are likely present in these groups, but they are generally too small to be efficiently observed with current technology.

These groupings of moons indicate that the early solar system was a very chaotic place, with constant movement and collisions between different objects.

Source: www.sci.news

Brightest Quasar Ever Observed Discovered by Astronomers

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The black hole in the newly discovered quasar SMSS J052915.80-435152.0 (J0529-4351) accretes about 1 solar mass per day on top of its existing mass of 17 billion solar masses.

This image of the exceptional quasar J0529-4351 is from the Dark Energy Camera Legacy Survey DR10. Adjacent M stars are displayed in red.Image credit: Wolf other., doi: 10.1038/s41550-024-02195-x.

In 1963, Dutch-born American astronomer Maarten Schmidt identified the first quasar, known as 3C 273. It appeared as a very bright star of magnitude 12, and its redshift suggested that it was one of the most distant objects known in the universe. time.

These two facts suggest an incredibly huge light output, and ever since, newly discovered quasars have impressed with their ability to emit enormous amounts of energy from small regions of the universe. Ta.

This can only be explained by the conversion of gravitational energy into heat and light in a highly viscous accretion disk around a supermassive black hole.

Currently, about 1 million quasars are known, but a few specimens stand out. In 2015, ultraluminous quasar J0100+2802 was confirmed to be a supermassive black hole with 10 billion solar masses.

In 2018, an even brighter object, J2157-3602, was discovered, which contains a supermassive black hole with a mass of 24 billion solar masses.

Its brightness suggests rapid growth, but its existence is difficult to explain. When black holes start from the debris of a star's collapse and grow temporarily, they are not expected to reach appreciable mass in the time between the Big Bang and the black hole era. observation.

The quasar that broke the new record is so far from Earth that it took more than 12 billion years for its light to reach us.

The object, called J0529-4351, was first detected using the 2.3 meter telescope at the ANU Siding Spring Observatory.

Australian National University astronomer Christian Wolff and colleagues then turned to ESO's Very Large Telescope, one of the world's largest telescopes, to confirm the full nature of the black hole and measure its mass. Toward.

“We have discovered the fastest growing black hole ever known. It has a mass of 17 billion suns and eats just over one sun a day. This makes it the fastest growing black hole in the known universe. It will be a bright object,” Dr. Wolf said.

The material drawn into this black hole in the form of a disk emits so much energy that J0529-4351 is more than 500 trillion times brighter than the Sun.

“All this light comes from a hot accretion disk seven light-years in diameter, which must be the largest accretion disk in the universe,” said Dr. Student Samuel Lai.

“Given what we know about many other less impressive black holes, it's surprising that it hasn't been detected before. It was hiding in plain sight,” says the Australian National said Dr. Christopher Onken of the university.

This finding is reported in the following article: paper in diary natural astronomy.

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C.Wolf other. Accretion of solar masses per day by a 17 billion solar mass black hole. Nat Astron, published online on February 19, 2024. doi: 10.1038/s41550-024-02195-x

Source: www.sci.news

Astronomers find hundreds of massive gas clouds streaming away from the Milky Way’s center

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Using new 21 cm radio observations made with NSF's Green Bank Telescope, astronomers have discovered that more than 250 clouds of neutral gas are blasting out into interstellar space from the center of the Milky Way. These clouds are likely the product of the same phenomenon that created the Fermi bubble.

The artist's concept is that clouds flowing from the center of the Milky Way are caught up in extremely hot winds and accelerated to speeds of hundreds of kilometers per second. Image credit: NSF/GBO/P. Vosteen.

It has long been known that energetic processes at the center of the Milky Way generate high-velocity hot winds that spread through intergalactic space with temperatures of millions of degrees and speeds of thousands of kilometers per second. Most large galaxies have winds like this.

The serendipitous discovery that some of this hot gas is trapped in cold hydrogen clouds was made by Australia's ATCA telescope, which measured 21cm radio emissions from interstellar hydrogen atoms.

This suggests that there may be an undiscovered population of clouds transporting material away from the Milky Way's core.

Hydrogen clouds are important in their own right, but they also act as probes for hot air.

Conditions in very hot winds are difficult to measure, but just as a few leaves thrown up on Earth indicate the direction and speed of the wind in the area, cold clouds can You can track its status.

The sensitivity of the Green Bank Telescope (GBT) makes it an ideal instrument for detecting faint signals from interstellar hydrogen, but mapping these clouds and understanding their true extent is essential. It wasn't easy.

Dr Felix James 'Jay' Rockman, senior astronomer at Green Bank Observatory, said: 'It took many years to systematically map hundreds of square degrees using GBT in search of weak hydrogen emissions. ” he said.

“Once we identify a few promising candidates, we can follow up with targeted observations with other telescopes to show us even more.”

“This cloud must have been ripped off from a region near the center of the Milky Way galaxy and flung outward by a burst of star formation or black hole activity.”

Some of these clouds have the fastest outflow velocities of any cloud ever observed in the Milky Way, and may even escape from the Milky Way.

In an unexpected development, new data from the APEX telescope reveals that some hydrogen clouds contain molecules and dense cold gas.

“No one would have expected that the clouds violently ejected from the Milky Way would harbor relatively fragile molecular material, but that's what happened,” Rockman said.

Astronomers using the MeerKAT array recently mapped hydrogen in several clouds with high angular resolution, showing that it evolves and gets shredded as it flows into interstellar space.

“These new results open the door to further discoveries,” Dr. Rockman said.

“How clouds that are accelerated to speeds of more than 400 kilometers per second remain stable is a mystery.”

“The chemical processes inside these clouds are very unusual and unexplored.”

Dr. Rockman and his colleague Dr. Enrico Di Teodoro of the University of Florence, findings in AAS243243rd Meeting of the American Astronomical Society, New Orleans, Louisiana, USA.

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Felix Rockman and Enrico di Teodoro. 2024. New investigation of neutral clouds in the Milky Way's core wind. AAS243Abstract #2851

Source: www.sci.news

Binary System of Free-Floating Planet-Mass Objects Discovered by Astronomers

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The JuMBO 24 binary system resides in the Orion Nebula, a diffuse nebula located approximately 1,350 light-years away in the constellation Orion.

Free-floating Jupiter-mass binary objects are common, even if current stellar and planetary theory cannot explain their existence. Image credit: Gemini Observatory / Jon Lomberg.

Professor Luis Rodriguez of the National Autonomous University of Mexico and his colleagues said, “Near-infrared surveys of the interior of the Orion Nebula and the Trapezoid Cluster using the James Webb Space Telescope (JWST) revealed 40 Jupiter-mass binary objects (JuMBOs) and 2 triple objects. were detected.” .

“These systems are not associated with stars, their component masses range from 0.6 to 14 times the mass of Jupiter, and their distances in the plane of the sky range from 28 to 384 AU. It’s between.”

“The existence of these widespread binaries is surprising because our current knowledge of star and planet formation cannot explain them.”

Using NSF's Carl G. Jansky Very Large Array (VLA), astronomers searched for the equivalent of 40 JuMBOs.

Surprisingly, only one of these objects, JuMBO 24, displayed a radio.

The radio brightness of the two planetary mass objects in this system is significantly higher than that detected in the brown dwarf.

This anomaly raises new questions and provides exciting research opportunities to further understand the nature of these free-floating planets.

While it's possible that the link between the infrared and radio signals is a coincidence, the researchers believe this is extremely unlikely, only 1 in 10,000.

“What's really remarkable is that these objects may have moons similar to Europa and Enceladus, both of which have underground oceans of liquid water that can support life,” Professor Rodriguez said. Told.

“The detection of radio waves emanating from both components of a dual system of free-floating planets represents an important milestone in our space exploration.”

“It also provides an exciting opportunity for further research into the potential habitability of planets beyond our solar system.”

of study Published in Astrophysics Journal Letter.

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Luis F. Rodriguez other. 2024. The radio counterpart of the Jupiter-mass binary object in Orion. APJL 960, L14; doi: 10.3847/2041-8213/ad18ac

Source: www.sci.news

Super-Earth exoplanet found within habitable zone of TOI-715 by astronomers

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Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers discovered a habitable zone planet orbiting nearby red dwarf star TOI-715 every 19.3 days and characterized its characteristics. I made it clear. They also demonstrated that a second, smaller exoplanet with a period of 25.6 days may exist, located just inside the outer edge of TOI-715’s habitable zone. This system represents the first of his TESS discoveries to fall within this most conservative and widely applicable habitable zone.

Artist’s impression of the super-Earth exoplanet TOI-715b. Image credit: NASA/JPL-Caltech.

TOI-715 is an M dwarf star of spectral type M4 located approximately 137 light-years away in the constellation Urae.

The star, also known as TIC 271971130, is about 6.6 billion years old, making it older than the Sun.

TOI-715 includes the super-Earth exoplanet TOI-715b and the smaller terrestrial exoplanet candidate TOI-715c.

“TOI-715b is about 1.5 times wider than Earth and orbits within the habitable zone around its parent star,” said Georgina Dransfield, an astronomer at the University of Birmingham.

“This is the distance from the star that can give the planet the right temperature for liquid water to form on its surface.”

“Of course, for surface water to exist, several other factors have to be in place, especially for us to have a suitable atmosphere.”

“However, the conservative habitable zone (which may be narrower and more robustly defined than the broader ‘optimistic’ habitable zone) is a It ranks first.”

“A smaller planet, TOI-715c, may be only slightly larger than Earth and may exist just inside the conservative habitable zone.”

“TOI-175b joins the list of habitable zone planets that could be scrutinized more closely by Webb, perhaps also for atmospheric signatures,” the astronomers said.

“A lot depends on other properties of the planet, such as how heavy it is and whether it can be classified as a water world. Its atmosphere, if any at all, is more massive, denser, and has an atmosphere. It’s less pronounced than the atmosphere, and much less difficult to detect. Drier worlds are likely to keep their inconspicuous atmospheres close to the surface.”

“If the possibility of a second Earth-sized planet in this system is confirmed, it would be the smallest habitable zone planet ever discovered by TESS.”

“This discovery also exceeds TESS’s initial expectations by discovering an Earth-sized world within the habitable zone.”

This finding is reported in the following article: paper inside Royal Astronomical Society Monthly Notices.

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Georgina Dransfield other. 2024. Earth's habitable zone planet hosted by the M4 star TOI-715 near the ecliptic south pole. MNRAS 527 (1): 35-52; doi: 10.1093/mnras/stad1439

Source: www.sci.news

Astronomers solve the enigma of enigmatic radio circles

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The odd radio sphere (ORC), a type of extragalactic astronomical source discovered in 2019, is actually a shell formed by galactic winds spilling from massive supernovae, according to a new study.

ASKAP radio continuum image (contours) of ORC 1 superimposed on the DES tricolor composite image. Two galaxies of interest: 'C' is near the center of ORC 1, and 'S' coincides with the southern radio peak. Image credit: Norris otherarXiv: 2006.14805.

The first three ORCs were discovered during the Cosmic Evolution Map pilot survey using the Australian Square Kilometer Array Pathfinder (ASKAP) telescope.

A fourth ORC, called ORC4, was discovered in archival data taken with the Giant Meterwave radio telescope, and additional ORCs were discovered in subsequent ASKAP and MeerKAT data.

These sources are huge, hundreds of kiloparsecs across, with one kiloparsec equal to 3,260 light-years.

Multiple theories have been proposed to explain its origin, including planetary nebulae and black hole mergers, but it was not possible to distinguish between the theories based on radio data alone.

Intrigued, Professor Alison Coyle of the University of California, San Diego, and colleagues thought that the radio rings could have originated from the later stages of the starburst galaxies they were studying.

Until then, ORCs had only been observed by radio emission, and no optical data were available.

Astronomers observed ORC 4 using the Integrating Field Spectrometer at W.M. Keck Observatory on Mauna Kea, Hawaii, and found that it contained a huge amount of high-brightness, much more than is seen in the average galaxy. A heated compressed gas was revealed.

With more questions than answers, the team set to work doing some detective work.

Using optical and infrared imaging data, they determined that the stars in the ORC 4 galaxy are about 6 billion years old.

“This galaxy experienced an explosion of star formation that ended about a billion years ago,” Professor Coyle said.

The authors also ran a series of numerical computer simulations to recreate the size and properties of the massive radio ring containing large amounts of shocked cold gas in the central galaxy.

Simulations show that the outflowing galactic winds will continue to blow for 200 million years before stopping.

When the winds stopped, forward shocks continued to push hot gas out of the galaxy, forming a radio ring, while reverse shocks caused cooler gas to fall into the galaxy.

The simulation ran for 750 million years. This is within ORC 4's estimated stellar age of 1 billion years.

“For this to work, you need a high mass egress rate, which means you're releasing a lot of material very quickly,” Professor Coyle says.

“And the surrounding gas just outside the galaxy has to be low density, otherwise the shock stalls. Those are the two key factors.”

“We found that the galaxies we have studied have high rates of mass outflow. Although rare, they do exist. This points to ORC originating from some type of outflow galactic wind. I really think so.”

Outflow winds not only help astronomers understand ORCs, but ORCs also help astronomers understand outflow winds.

“ORC provides a way to 'see' the wind through radio data and spectroscopy,” Professor Coyle said.

“This will help us determine how common extreme outflow winds from galaxies are and what the life cycle of winds is like.”

“These can also help us learn more about galaxy evolution. Do all giant galaxies go through an ORC phase?”

“Do spiral galaxies become elliptical when they stop forming stars? I think there's a lot we can learn about and from the ORC.”

of study It was published in the magazine Nature.

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AL coil other. Ionized gas extends beyond 40 kpc within odd radio host galaxies. Nature, published on January 8, 2024. doi: 10.1038/s41586-023-06752-8

Source: www.sci.news

Astronomers believe at least two supernova explosions produced supernova remnant 30 Doradas B

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30 Doradas BThis galaxy, also cataloged as NGC 2060, is discovered in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way.


At the center of this complex landscape of bright, colorful gas clouds is the supernova remnant 30 Doradas B. Image credit: NASA / CXC / Pennsylvania State University / Townsley other. / STScI / HST / JPL / CalTech / SST / SAO / J. Schmidt / N. Wolk / K. Arcand.

30 Doradus B is part of a large star-forming region where stars have been forming continuously over the past 8 to 10 million years.

It is located 160,000 light-years from Earth in the Large Magellanic Cloud, a complex landscape of dark clouds of gas, young stars, high-energy shocks, and superheated gas.

In a new study, astronomer Weian Chen of National Taiwan University and his colleagues used 30 high-resolution images of the Doradas B type from several telescopes on the ground and in space, including NASA/ESA's Hubble Space Telescope and the Australian Square Kilometer Array Pathfinder. The resolution multi-wavelength images were analyzed. , NASA's Spitzer Space Telescope and Chandra X-ray Observatory.

Researchers detected a faint X-ray shell about 130 light-years in diameter.

Chandra's data also revealed that 30 Doradas B contains a wind of particles blown away from the pulsar, forming what is known as a pulsar wind nebula.

Combining data from Hubble and other telescopes, researchers determined that a single supernova explosion could not explain what they were seeing.

Both the pulsar and the bright X-rays seen at the center of Doradas 30 B may have resulted from a supernova explosion after the collapse of a massive star about 5,000 years ago.

But the larger, dimmer X-ray shell is too large to have come from the same supernova.

“Rather, we believe that at least two supernova explosions occurred in Doradas 30 B, using X-ray shells produced by another supernova more than 5,000 years ago,” the scientists said.

“It's quite possible that more has happened in the past.”

“These results will help us learn more about the lives of massive stars and the effects of supernova explosions.”

a paper Regarding the survey results, astronomy magazine.

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Chen Weian other. 2023. New insights about 30 Dor B revealed by high-quality multiwavelength observations. A.J. 166, 204; doi: 10.3847/1538-3881/acff72

Source: www.sci.news

New Method Discovered by Astronomers for Detecting Water Oceans and Alien Life on Rocky Exoplanets

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Planets that are too close to their star (such as Venus) are too hot, and planets that are too far away (such as Mars) are too cold, but planets that are within the habitable zone have just the right temperature. Although great efforts have been made to identify planets in the theoretical habitable region of stars, until now there has been no way to know whether a planet really has liquid water. Now, astronomers from the University of Birmingham and the Massachusetts Institute of Technology have found that if an exoplanet’s atmosphere has less carbon dioxide than its neighbors, it may have liquid water on its surface. It was shown that it was suggested.

Artist’s impression of the super-Earth planet Ross 508b. Image credit: Sci.News.

Astronomers have detected more than 5,200 extrasolar worlds so far. Modern telescopes allow us to directly measure the distance from a planet to a star and the time it takes to complete one revolution.

These measurements help scientists infer whether a planet is within its habitable zone.

However, there was no way to directly confirm whether a planet was truly habitable, i.e. whether there was liquid water on its surface.

Throughout our solar system, astronomers can detect the presence of liquid oceans by observing glints, flashes of sunlight reflecting off liquid surfaces.

These glows, or specular reflections, have been observed, for example, on Saturn’s largest moon, Titan, and helped identify the moon’s large lakes.

However, detecting similar glows on distant planets is not possible with current technology.

But astronomer Julien de Witt of the Massachusetts Institute of Technology, astronomer Amaury Tryaud of the University of Birmingham and colleagues believe there is another habitable landform close to home that could be detected far away. I noticed something.

“Looking at what was happening to terrestrial planets in our own star system gave us an idea,” Tryaud said.

Venus, Earth, and Mars share similarities in that all three are rocky and live in relatively temperate regions relative to the Sun.

Earth is the only planet of the three that currently has liquid water. Researchers then noted another clear difference. That means there is significantly less carbon dioxide in Earth’s atmosphere.

“We think these planets formed in a similar way, and if we find a planet with less carbon than it does now, it must have gone somewhere else,” Tryaud said.

“The only process that can remove this much carbon from the atmosphere is a strong water cycle involving oceans of liquid water.”

In fact, Earth’s oceans have played a major and persistent role in absorbing carbon dioxide.

For hundreds of millions of years, the ocean has absorbed enormous amounts of carbon dioxide. This is about the same amount that remains in Venus’ atmosphere today.

This planetary effect has resulted in Earth’s atmosphere being significantly depleted in carbon dioxide compared to neighboring planets.

Dr. Frieder Klein, a researcher at the Woods Hole Oceanographic Institution, said: “On Earth, much of the carbon dioxide in the atmosphere is sequestered in seawater and solid rock over geological timescales; It has helped regulate climate and habitability for billions of years.” .

Astronomers reasoned that if a similar decrease in carbon dioxide was detected on a distant planet compared to a nearby planet, this would be a reliable signal of a liquid ocean and life on its surface. did.

“After an extensive review of the literature in many fields, from biology to chemistry to carbon sequestration related to climate change, we found that if carbon depletion is indeed detected, it is likely that liquid water and its effects are “We think this is likely a strong indication that this is a sign of life.” Dr. de Witt said.

In the study, the researchers developed a strategy to detect habitable planets by looking for traces of depleted carbon dioxide.

Such searches are ideal for “pea” systems, like our solar system, in which multiple terrestrial planets, all about the same size, orbit relatively close to each other.

The first step, the scientists suggest, is to confirm that a planet has an atmosphere by simply looking for the presence of carbon dioxide, which is expected to dominate the atmospheres of most planets.

“Carbon dioxide is a very strong absorber of infrared light and can be easily detected in the atmospheres of exoplanets,” Dr. de Witt said.

“The carbon dioxide signal could reveal the presence of an exoplanet’s atmosphere.”

Once astronomers determine that multiple planets in a system have atmospheres, they move on to measuring their carbon dioxide content to see if one planet has significantly less than the others.

If so, this planet is likely habitable, which means there is a large amount of liquid water on its surface.

However, habitable conditions do not necessarily mean that the planet is inhabited. To confirm whether life actually exists, the authors suggest that astronomers look for another feature in the planet’s atmosphere: ozone.

On Earth, plants and some microorganisms contribute to absorbing carbon dioxide, although to a lesser extent than the oceans. Nevertheless, as part of this process, living organisms release oxygen, which reacts with solar photons and turns into ozone. Ozone is a much easier molecule to detect than oxygen itself.

If a planet’s atmosphere shows signs of both ozone and carbon dioxide depletion, the planet may be habitable and inhabited by humans.

“If you see ozone, there’s a pretty good chance it’s related to carbon dioxide being consumed by life forms,” ​​says Tryaud.

“And if it’s life, it’s glorious life. It won’t be just a few bacteria. It’ll be a planetary-scale biomass that can process and interact with large amounts of carbon.”

The researchers believe NASA/ESA/CSA’s James Webb Space Telescope can measure carbon dioxide, and possibly ozone, in nearby multiplanetary systems like TRAPPIST-1, a seven-planet system orbiting a bright star. I’m guessing it is. Light years from Earth.

“TRAPPIST-1 is one of the few systems that can use the Web to study Earth’s atmosphere,” said Dr. de Witt.

“We now have a roadmap to finding habitable planets. If we all work together, we may make paradigm-changing discoveries within the next few years.”

of study It was published in the magazine natural astronomy.

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AHMJ triode other. Atmospheric carbon depletion as a tracer of water oceans and biomass in temperate terrestrial exoplanets. Nat Astron, published online on December 28, 2023. doi: 10.1038/s41550-023-02157-9

Source: www.sci.news

Astronomers find frequent and energetic fast radio bursts

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FRB 20220912A is a repetitive high-speed radio burst discovered in 2022 that remained highly active for several months.Use recently updated one allen telescope arraySETI Institute astronomers recorded 35 bursts from 541 hours of follow-up observations over two months of the FRB 20220912A source and found that an interesting pattern had emerged.

Artist’s impression of FRB 110523 as it reaches Earth. The colors represent bursts arriving at different radio wavelengths, with longer wavelengths (red) arriving a few seconds after shorter wavelengths (blue). Image credit: Jingchuan Yu / Beijing Planetarium.

Fast radio bursts (FRBs) are mysterious and rarely detected bursts of energy that come from beyond the Milky Way.

These events have a duration of milliseconds and exhibit the characteristic dispersive sweep of radio pulsars.

They emit as much energy in one millisecond as the sun does in 10,000 years, but the physical phenomena that cause them are unknown.

More than 100 FRBs have been detected to date, but only some of them have been observed to replicate so far.

Like most repeating FRBs, each burst from FRB 20220912A drifted from higher to lower frequencies over time.

However, the center frequency of the bursts also showed a previously unseen drop, and when converted to audible sounds using xylophone sounds, it became clear that they sounded like cosmic slide whistles.

In this song, most of the highest notes are heard in the first few seconds, and most of the lowest notes are heard in the last few seconds, as if the xylophone player was repeatedly hitting the lowest available bars on the instrument. .

Astronomers believe that at least some FRBs are produced by neutron stars known as magnetars, while other theories point to binary neutron star collisions or white dwarf mergers.

Dynamic spectra, frequency-averaged pulse profiles, and time-averaged spectra of all bursts from FRB 20220912A detected using the Allen telescope array.Image credit: Shake other. /SETI Institute.

“This study is exciting because it provides both confirmation of known FRB properties and the discovery of several new properties,” said Dr. Sophia Sheikh, lead author of the study.

“We have narrowed down the source of FRBs to extreme objects, such as magnetars, but no existing model can explain all the properties observed so far.”

Dr. Sheikh and his colleagues made this discovery after 541 hours of observations using the SETI Institute’s Allen Telescope Array.

They also tried to identify patterns in the timing between bursts, but found none. This further illustrates the unpredictable and mysterious nature of these powerful radio bursts.

Nevertheless, the latest research marks another step in the quest to unlock the secrets of FRBs, which generate as much energy in a thousandth of a second as the sun does in a year.

“It was great to be part of the first FRB study conducted using the Allen Telescope Array,” said Dr. Sheikh.

“This study proves that new telescopes with unique capabilities like the Allen Telescope Array can provide new angles on outstanding mysteries in FRB science.”

of the team paper will be published in Royal Astronomical Society Monthly Notices.

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Sophia Z. Sheikh other. 2023. Characterization of iterative FRB 20220912A using the Allen Telescope Array. MNRAS, in press. arXiv: 2312.07756

Source: www.sci.news

A cluster of stripped helium stars found in the Magellanic Cloud by astronomers

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Removing the hydrogen-rich layer from a main-sequence star exposes the helium-rich core. Such stripped helium stars are known at high and low masses, but not at intermediate masses, despite theoretical predictions that they should be common. In a new study, astronomers at the University of Toronto and elsewhere used ultraviolet photometry to identify candidates for stripped helium stars in two nearby dwarf galaxies, the Large and Small Magellanic Clouds. We observed 25 such candidate stars using optical spectroscopy. Most of these systems have been shown to be binary systems, with the companion star likely stripping the helium star of its outer hydrogen-rich layer.

An artist’s impression of a large-scale binary system. Image credit: ESO / M. Kornmesser / SE de Mink.

The hydrogen-rich outer layers of massive stars can be removed by interactions with binary companions.

Theoretical models predict that this separation would produce a population of hot helium stars with masses between two and eight times the mass of the Sun, but only one such system has been identified to date.

“This was a very large and noticeable hole. If these stars turn out to be rare, it could affect supernovae, gravitational waves, light from distant galaxies, and our theories for all these different phenomena. The whole framework is wrong,” said Dr Maria Draut, an astronomer at the university. of Toronto.

“This discovery shows that these stars actually exist.”

“In the future, we will be able to perform even more detailed physics on these stars.”

“For example, predictions of how many neutron star mergers we will see depend on the properties of these stars, such as how much material is ejected by stellar winds.”

“In the past, people have estimated it, but now for the first time they will be able to measure it.”

Dr. Drout and her colleagues designed a new study to look at the ultraviolet part of the spectrum, where very hot stars emit most of their light.

Astronomers used data from the Swift Ultraviolet/Optical Telescope to collect the brightness of millions of stars in the Large and Small Magellanic Clouds, the two closest galaxies to Earth.

They developed the first wide-field UV catalog of the Magellanic Clouds and used UV photometry to detect systems with unusual UV emissions indicating the possible presence of stripped stars.

They acquired optical spectroscopy with the Magellan Telescope at the Las Campanas Observatory from 2018 to 2022 and conducted pilot studies on 25 objects.

These stripped stars had high temperatures (60,000 to 100,000 K), high surface gravity, and hydrogen-depleted surfaces. Sixteen stars also showed binary motion.

Drout and his co-authors propose that these stars will eventually explode as hydrogen-depleted supernovae.

These objects, like the gravitational wave-emitting objects detected from Earth by the LIGO experiment, are also thought to be necessary for the formation of neutron star mergers.

In fact, researchers believe that some of the objects in the current sample are neutron stars or stripped stars with black hole companions.

These objects are on the verge of becoming double neutron stars or neutron star and black hole systems that may eventually merge.

“Many stars are part of a cosmic dance with partners, orbiting each other in binary star systems,” says Dr. Bethany Ludwig. He is a student at the University of Toronto.

“They are not solitary giants, but part of a dynamic duo, interacting and influencing each other throughout their lives.”

“Our research sheds light on these fascinating relationships, revealing a universe far more interconnected and active than previously imagined.”

“Just as humans are social beings, stars, especially massive stars, are rarely lonely.”

of result appear in the diary science.

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MR Drought other. 2023. Observed population of intermediate-mass helium stars separated by binaries. Science 382 (6676): 1287-1291; doi: 10.1126/science.ade4970

Source: www.sci.news

Astronomers make breakthrough discovery in planet formation, conflicting with theoretical predictions

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Recent observations of the young star DG Taurus reveal a smooth protoplanetary disk in which no planets have yet formed, suggesting that it is on the brink of this process. The findings show unexpected dust grain growth patterns and provide new insights into the early stages of planet formation. Credit: SciTechDaily.com

Astronomers have become very good at finding signs of planet formation around stars. However, to fully understand planet formation, it is important to examine cases where this process has not yet begun.

Looking for something and not finding it can sometimes be even more difficult than finding it, but new detailed observations of the young star DG Taurus reveal that the planet is a smooth protoplanet with no signs of planet formation. It was shown that it has a system disk. This lack of detected planet formation may indicate that DG Taurus is on the eve of planet formation.

Image of radio radiation intensity from a disk near DG Taurus observed with ALMA. Rings have not yet formed within the disk, suggesting that planets are about to form.Credit: ALMA (ESO/National Astronomical Observatory/NRAO), S. Obashi et al.

Protoplanetary disk and planet growth

Planets form around protostars, which are young stars that are still forming, in disks of gas and dust known as protoplanetary disks. Planets grow so slowly that it is impossible to observe their evolution in situ. Therefore, astronomers observe many protostars at slightly different stages of planet formation to build theoretical understanding.

This time, an international research team led by Satoshi Ohashi of the National Astronomical Observatory of Japan (NAOJ) has developed the Atacama Large Millimeter/Submillimeter Array (alma telescope) will conduct high-resolution observations of the protoplanetary disk surrounding the relatively young protostar DG Taurus, located 410 light-years away in the direction of Taurus. The researchers found that DG Taurus has a smooth protoplanetary disk and no rings that would indicate planet formation. This led the research team to believe that the DG Taurus system could begin forming planets in the future.

Unexpected discoveries and future research

The researchers found that during this pre-planetary stage, dust particles are within 40 astronomical units (about twice the size of Earth’s orbit). Uranus The radius of the central protostar is still small, but beyond this radius the dust particles begin to grow, which is the first step in planet formation. This goes against the theoretical expectation that planet formation begins inside the disk.

These results provide surprising new information about dust distribution and other conditions at the beginning of planet formation. Studying more examples in the future will further deepen our understanding of planet formation.

Reference: “Dust concentration and particle growth in the smooth disk of a DG tau protostar revealed by ALMA triple-band frequency observations” Satoshi Ohashi, Munetake Momose, Akiraka Kataoka, Aya Higuchi E, Takashi Tsukagoshi, Takahiro Ueda, Claudio Codella, Linda Podio, Tomoyuki Hanawa, Nami Sakai, Hiroshi Kobayashi, Satoshi Okuzumi, Hidekazu Tanaka, August 28, 2023, of astrophysical journal.
DOI: 10.3847/1538-4357/ace9b9

This research was funded by the Japan Society for the Promotion of Science, the German Foundation, and the European Union.

Source: scitechdaily.com

Three new young stars found in the central region of the Milky Way galaxy by astronomers

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According to some researchers, the oldest of these stars is 1.5 billion years old, while the youngest is only 100 million years old. paper Published in Astrophysics Journal Letter.

This infrared image from Hubble shows the Milky Way Core Cluster, the densest and most massive star cluster in our galaxy. Image credit: NASA / ESA / Hubble Heritage Team / STScI / AURA / T. Do & A. Ghez, UCLA / V. Bajaj, STScI.

The center of our Milky Way galaxy is located about 27,000 light-years away in the constellation Sagittarius and is a crowded place.

This region is so dense that it’s equivalent to a million stars crammed into the space between the Sun and Alpha Centauri, 4.3 light-years away.

This nuclear cluster surrounds Sagittarius A*, a 4.3 million solar mass black hole at the center of the galaxy.

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In general, many nuclear star clusters coexist with supermassive black holes, which are found in more than 70% of galaxies with masses greater than 100 million to 10 billion solar masses.

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“In previous work, we hypothesized that these particular stars in the middle of the Milky Way may be unusually young,” said Lund University astronomer Rebecca Forsberg.

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“Now we can confirm this. Our study shows that three of these stars are relatively young, at least as far as astronomers are concerned, ranging in age from 100 million years to about 1 billion years. We were able to determine the age.”

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“This is equivalent to the age of the Sun, which is 4.6 billion years old.”

This panorama shows the central region of the Milky Way galaxy. It builds on previous surveys by NASA’s Chandra X-ray Observatory and other telescopes, and extends Chandra’s high-energy field of view further up and down the galactic plane than previous imaging campaigns. The X-rays from Chandra are orange, green, and violet, indicating different X-ray energies. Radio data from MeerKAT is gray. Image credits: NASA / CXC / UMass / QD Wang / NRF / SARAO / MeerKAT.

In this study, Dr. Forsberg and colleagues used high-resolution data from the Keck II telescope in Hawaii. This Keck II telescope is one of the largest telescopes in the world with a 10 meter diameter mirror.

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For further verification, they measured the amount of iron, a heavy element, in the stars

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This element is important in tracking the development of galaxies. This is because astronomers’ theories about star formation and galaxy development show that the formation of heavy elements increases over time in the Universe, so younger stars contain more heavy elements.

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To determine iron levels, astronomers looked at the star’s spectrum in infrared light. Infrared light is a part of the light spectrum that can more easily illuminate dust-dense parts of the Milky Way compared to optical light.

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Researchers say there is considerable variation in iron levels.

“The very wide spread in iron levels could indicate that the innermost parts of the galaxy are incredibly heterogeneous, or unmixed,” said Dr. Brian Thorsbro, an astronomer at Lund University. Stated.

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“This is something we didn’t expect, and it tells us something not only about what the center of a galaxy looks like, but also about what the early universe looked like.”

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“Personally, I think it’s very exciting that we can now study the galactic center itself at such a detailed level,” Dr. Forsberg said.

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“While these types of measurements have been standard for observations of our own galactic disk, they have been an unattainable goal in more remote and exotic parts of the galaxy.”

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“Studies like this can teach us a lot about how our home galaxy formed and developed.”

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B. Thorsbro other. 2023. The range of old metallicities of stars in nuclear clusters is wide. APJL 958, L18; doi: 10.3847/2041-8213/ad08b1

Source: www.sci.news