Tag Archives: spots

Research on the various cloud layers, temperature hot spots, and shifting chemistry found in the extraterrestrial realm

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New observations from the NASA/ESA/CSA James Webb Space Telescope support the presence of three specific functions in the atmosphere (clouds, hot spots, and changes in carbon chemistry) of the rapidly rotating and free floating planetary mass object SIMP J013656.5+093347.

Impressions of the artist of SIMP 0136. Image credits: NASA/ESA/CSA/J. Olmsted, Stsci.

SIMP J013656.5+093347 (SIMP 0136 for short) is a rapidly rotating, free-floating object located just 20 light years from Earth.

It may have a mass of 13 Jupiter masses, does not orbit the star, and instead may be a brown dwarf.

Because it is separated, SIMP 0136 can be directly observed and is not afraid of mild contamination or variability caused by the host star.

The short rotation period, only 2.4 hours, allows for very efficient investigation.

“We've been working hard to get into the world,” said Allison McCarthy, a doctoral student at Boston University.

“We also thought that it might have an effect on temperature fluctuations, chemical reactions, and perhaps the activity of the aurora affecting brightness, but we weren't sure.”

Webb's NirSpec Instruments We captured thousands to 5.3 micron spectra of SIMP 0136. The object completed one full rotation, so I captured it one at a time, one at a time, one at a time, one at a time, over 3 hours.

This led to immediate observation Webb's Milli Musical Instrumentshundreds of measurements of light between 5 and 14 microns were collected. One is one every 19.2 seconds, one in another rotation.

The results were hundreds of detailed rays, each showing a very accurate wavelength (color) brightness change, with different sides of the object rotating into view.

“It was incredible to see the entire range of this object change over a few minutes,” said Dr. Joanna Foss, an astronomer at Trinity College Dublin.

“Until now, we only had a small near-infrared spectrum from Hubble, but we had some brightness measurements from Spitzer.”

Astronomers almost immediately noticed that there were several distinct ray shapes.

At any time, some wavelengths were growing brightly, while others were either dimmed or not changing at all.

Many different factors must affect brightness variation.

“Imagine looking at the Earth from afar,” said Dr. Philip Muirhead, a former member of Boston University.

“Looking each color individually gives you a variety of patterns that tell you something about the surface and the atmosphere, even if you don't understand the individual features.”

“As the ocean rotates towards vision, blue increases. The brown and green changes tell us something about the soil and vegetation.”

To understand what could cause variability in SIMP 0136, the team used an atmospheric model to show where each wavelength of light is occurring in the atmosphere.

“The different wavelengths provide information about the different depths in the atmosphere,” McCarthy said.

“We began to realize that the wavelengths that had the most similar ray shapes also investigated the same depth and reinforced this idea that they must be caused by the same mechanism.”

For example, one group of wavelengths occurs deeply in the atmosphere where there may be patchy clouds made of iron particles.

The second group comes from high clouds, which are thought to be made from small grains of silicate minerals.

Both of these light curve variations are related to the patchiness of the cloud layers.

The third group of wavelengths appears to be occurring at very high altitudes far above the clouds and tracking temperatures.

Bright hotspots may be associated with previously detected auroras at radio wavelengths, or hot gas upwelling from deeper in the atmosphere.

Some light curves cannot be explained by clouds or temperature, but instead show variations related to atmospheric carbon chemistry.

There may be chemical reactions in which carbon monoxide and carbon dioxide pockets rotate within and outside of view, or alter the atmosphere.

“We still don't understand the chemical part of the puzzle yet,” Dr. Vos said.

“But these results are really exciting because they show that the richness of molecules like methane and carbon dioxide can change over time from location.”

“If you're looking at a deplanet and only have one measurement, you should assume that it may not be representative of the entire planet.”

Survey results It will be displayed in Astrophysics Journal Letter.

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Allison M. McCarthy et al. 2025. JWST weather report from isolated exoplanet analog SIMP 0136+0933: pressure-dependent variability driven by multiple mechanisms. apjl 981, L22; doi: 10.3847/2041-8213/AD9EAF

Source: www.sci.news

A Giant Star’s Surface Reveals Star Spots, Observes Astronomers

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According to a team of astronomers from the Leibniz Institute for Astrophysics at the University of Potsdam, the XX triangular star, a bright K0 giant star in a binary star system located in the constellation Triangulum, exhibits chaotic, aperiodic star point behavior. That’s what it means. and Konkoli Observatory.

XX A star spot on the surface of the constellation Triangulum. Image credits: HUN-REN RCAES / Zs. Kushvari, MOME / Á. Radovani, AIP / K. Strassmeyer.

“Among the things that can be observed from a spatially resolved solar disk are the number, size and morphology of sunspots, their growth and decay, and their movement in latitude and longitude,” said lead author and director of the Leibniz Institute for Astronomy. said Professor Klaus Strassmeyer. Potsdam Astrophysics and Potsdam University, and their colleagues.

“Such spots are also seen on other stars and are called star spots.”

“We use indirect surface imaging techniques to invert the spectral line profile into an image of the stellar surface.”

“Typically we only get occasional snapshots of spots on a star’s surface, but the spots change systematically over time, and like the Sun, only then can we learn about the internal dynamos and structure of the target in question. Well known.”

“We chose the XX triangular star, one of the most speckled stars in the sky, for a more sustained application of Doppler imaging.”

XX triangle It is located about 640 light years away in the constellation Triangulum.

The star, also known as XX Tri or HD 12545, has a mass only 10% more than the Sun, a radius 10 times the Sun’s radius, and an effective temperature of 4630 K.

It has a rotation period of 24 days, which is synchronized with the orbital period of the binary star system.

XX Trigonum has previously been shown to contain a gigantic star spot with physical dimensions equivalent to 10,000 times the area of the largest group of spots ever seen on the Sun, and 10 times the size of the projected solar disk. It had been discovered in

Professor Strassmeier and his co-authors took 99 separate images of the star using an indirect surface imaging technique called Doppler imaging.

“A dark spot on the star’s surface caused its optical center (a point that essentially represents the star’s ‘center of light’) to shift by up to 24 microarcseconds, which is less than the radius of the star’s visible disk. This corresponds to approximately 10%,” they said. Said.

“These changes occur because the dark spots reduce the brightness of certain areas of the star, shifting the perceived center of light slightly.”

“However, unlike the sun’s predictable activity cycles, the displacements of these photocenters did not follow a periodic pattern. This is a largely chaotic and probably aperiodic pattern, very different from the solar dynamo. This suggests that it is a dynamo.”

“This phenomenon also highlights challenges in detecting exoplanets, as spot-induced fluctuations in the optical center can mimic or mask small movements caused by orbiting planets, which could impose substantial limitations on the detection of such exoplanets by astronomical observations.”

of findings appear in the diary nature communications.

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KG Strassmeyer others. 2024. XX Long-term Doppler images of triangular stars show chaotic aperiodic dynamos. Nat Commune 15, 9986; doi: 10.1038/s41467-024-54329-4

Source: www.sci.news

Hubble Space Telescope Spots Spiral of Condensation in NGC 2090

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Astronomers using the NASA/ESA Hubble Space Telescope have taken surprising new photos of spiral galaxy NGC 2090.

This Hubble image shows NGC 2090, a spiral galaxy located south of the constellation Columba, about 40 million light-years away. Color images were created from separate exposures taken in the ultraviolet, visible, and near-infrared regions of the spectrum using Hubble's Wide Field Camera 3 (WFC3). This is based on data obtained through six filters. Color is obtained by assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA / ESA / Hubble / D. Tilker.

NGC2090 It is a spiral galaxy located south of the constellation Columba.

Also known as ESO 363-23, IRAS 05452-3416, LEDA 17819. discovered It was announced by Scottish astronomer James Dunlop on October 29, 1826.

“NGC 2090 is notable as part of a group of galaxies being studied. Hubble's Extragalactic Distance Scale Key Project“This study aimed to determine a new, state-of-the-art value for the Hubble constant, one of the main scientific goals of the then-new telescope,” Hubble astronomers said in a statement.

“NGC 2090's contribution was to calibrate the Tully-Fisher (TF) distance method by observing Cepheid variable stars in the galaxy.”

“Cepheid-based measurements from a 1998 study estimated the distance of NGC 2090 to be 37 million light-years.”

“Latest measurements in 2020 using the TF method place NGC 2090 slightly further away, at 40 million light-years.”

Before and after that project, NGC 2090 has been well studied as a very prominent nearby example of star formation.

It has been described as a cotton-like spiral, meaning a spiral galaxy with a speckled, dusty disk and flaky or no visible arms.

“This Hubble image gives a good indication of why NGC 2090 received such a description, with its spiral arms looking like lanes of light winding through the dust,” the astronomers said. said.

“NGC 2090 remains an active galaxy, with clusters of star formation in various stages of evolution spread throughout the disk.”

“Investigating star formation and the movement of matter within galaxies was the motivation for these Hubble observations taken in October of this year.”

“Likewise, Hubble's partner in space astronomy, NASA/ESA/CSA's James Webb Space Telescope, also scouted this galaxy to add infrared data to the picture of galaxy evolution.”

Source: www.sci.news

VLT spots metallic scar on surface of white dwarf

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A dynamically active planetary system orbits a significant portion of the white dwarf. These stars often exhibit surface metals accreted from a disk of debris. However, the complete journey of a planetesimal from its star-grazing orbit to its final dissolution in its host star is poorly understood. In a new paper, Astrophysics Journal Letter astronomers report the discovery that stars exist that are contaminated with cold metals. WD 0816-310 It cannibalized heavy elements from a planetary body as large as the dwarf planet Vesta.

WD 0816-310 is a magnetic white dwarf star located 63 light-years away in the constellation Papis. Image credit: L. Calçada / ESO.

Dr Stefano Vanullo, an astronomer at the Armagh Observatory and Planetarium, said: 'It is common for some white dwarfs – slowly cooling embers of stars like our Sun – to cannibalize parts of planetary systems. known,” he said.

“Now we find that the star's magnetic field plays a key role in this process, causing scars on the white dwarf's surface.”

The metal signatures the researchers observed on WD 0816-310 are concentrations of metal imprinted on the white dwarf's surface.

Professor Jay Farihi of University College London said: “These metals come from fragments of a planet the size of, or possibly even larger than, Vesta, which at about 500 kilometers in diameter is the second largest asteroid in the solar system. I have proven that.”

To observe WD 0816-310, astronomers FORS2 equipment upon ESO's super large telescope (VLT).

They also relied on archival data from VLT. X shooter instrument This is to confirm the survey results.

The authors noticed that the strength of the metal detections changed as the star rotated, indicating that the metals were concentrated in specific areas on the white dwarf's surface, rather than being spread smoothly across the surface. Suggests.

They also found that these changes were synchronized with changes in the white dwarf's magnetic field, indicating that this metallic scar is located at one of its magnetic poles.

Taken together, these clues indicate that the magnetic field funneled metal into the star, creating the scar.

“Surprisingly, the material was not evenly mixed on the star's surface, as theory predicted. Instead, this scar was a concentrated patch of planetary material that guided falling debris. “We've never seen anything like this before,” said John Landstreet, a professor at Western University.

“ESO offers a unique combination of capabilities needed to observe faint objects like white dwarfs and make sensitive measurements of the star's magnetic field,” Vanullo said.

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Stefano Vanullo other. 2024. Discovery of magnetically induced metal accretion on contaminated white dwarfs. APJL 963, L22; doi: 10.3847/2041-8213/ad2619

Source: www.sci.news

Hubble spots a group of newly formed stars at the end of a colliding galaxy

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Using the NASA/ESA Hubble Space Telescope, astronomers observed seven interacting galaxies with long tadpole-like tidal tails of gas, dust, and numerous stars. Hubble’s exquisite clarity and sensitivity to ultraviolet light led to the discovery of 425 clusters of newborn stars along these tidal tails. Each cluster contains up to a million newborn blue stars.

As seen in this Hubble image, galaxy AM 1054-325 has been distorted from its usual pancake-like spiral shape into an S-shape by the gravity of its neighboring galaxies. As a result, clusters of newborn stars form along tidal tails stretching across thousands of light years, resembling strings of pearls. Image credit: NASA/ESA/STScI/Jayanne English, University of Manitoba.

Tidal tail star clusters have been known for decades. When galaxies interact, gravitational tidal forces pull out long streams of gas and dust.

Two commonly used examples are antennas and rat galaxy It has elongated finger-like projections.

In a new study, astronomer Michael Rodrak of Randolph-Macon College and his colleagues combined new observational data with archival data to determine the age and mass of the tidal tail cluster.

Researchers discovered that these star clusters are very young, only 10 million years old.

And they appear to be forming at the same rate along a tail that extends over thousands of light years.

“It’s surprising that there are so many young objects in the tail,” said Dr Rodrak, lead author of the paper. paper Published in Royal Astronomical Society Monthly Notices.

“It tells us a lot about cluster formation efficiency.”

“With tidal tails, a new generation of stars will be built that otherwise would not exist.”

Tidal tails look like spiral arms of galaxies extending into space.

The outer part of the arm is pulled like taffy by the gravitational tug of war between a pair of interacting galaxies.

Before the merger occurred, galaxies may have been rich in dusty clouds of hydrogen molecules that simply remained inert.

However, during the encounter, the clouds swayed and clashed.

This compressed the hydrogen and triggered the firestorm of star birth.

“The fate of these strung star clusters is uncertain,” the astronomers said.

“They remain intact under gravity and can evolve into globular clusters that orbit outside the plane of the Milky Way.”

“Alternatively, they could disperse and form a stellar halo around their host galaxy, or be thrown off and become stars that wander between galaxies.”

“This pearly star formation may have been more common in the early Universe, when galaxies were colliding with each other more frequently.”

“These nearby galaxies observed by Hubble are proxies for what happened in the distant past, and are therefore laboratories for studying the distant past.”

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michael rodrak other. 2023. Star clusters in tidal dust. MNRAS 526 (2): 2341-2364; doi: 10.1093/mnras/stad2886

Source: www.sci.news