Tag Archives: dwarfs

Astronomers Capture Direct Images of Brown Dwarfs Orbiting Nearby Red Dwarfs

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Astronomers utilized the Subaru Telescope, W.M. Keck Observatory, and ESA’s Gaia mission to capture images of the brown dwarf companion orbiting the M dwarf star LSPM J1446+4633.

NIRC2 image of J1446 taken in August 2023. The white arrow indicates the location of the new companion J1446B. Image provided by: Uyama et al., doi: 10.3847/1538-3881/ae08b6.

LSPM J1446+4633 (J1446) is a nearby mid-M dwarf, situated 17 parsecs (55 light-years) away.

The newly identified brown dwarf orbits its parent star at a distance approximately 4.3 times that of the Earth from the sun, completing an orbit every 20 years.

This object, designated J1446B, has a mass ranging from 20 to 60 times that of Jupiter.

“The success of this discovery was due to the combination of three complementary observational methods: (i) radial velocity (RV) measurements via long-term infrared spectroscopic monitoring by Subaru’s IRD instrument, (ii) high-resolution near-infrared imaging with advanced adaptive optics at the W.M. Keck Observatory, and (iii) precise astronomical acceleration measurements from ESA’s Gaia mission,” stated California State University astronomer Taichi Uyama and his team.

“By integrating these datasets and applying Kepler’s laws, we were able to determine the dynamic mass and orbital parameters of J1446B with unprecedented precision.”

“Radial velocity data by itself cannot differentiate between mass and orbital inclination, but the addition of direct imaging and Gaia data resolves this ambiguity.”

“The Subaru IRD-SSP program provided crucial RV data, while Keck’s cutting-edge adaptive optics allowed for the direct detection of the companion star at very close distances from the host star.”

“Previous studies have shown that astronomical acceleration from Hipparcos and Gaia can be combined with direct imaging to detect and analyze companion objects.”

“However, Hipparcos was unable to measure faint red dwarf stars like J1446.”

“Our study is the first to apply Gaia-only acceleration data to such a system, successfully constraining the orbit and dynamical mass of a brown dwarf companion.”

Near-infrared observations of J1446B indicated a brightness variation of about 30%, hinting at dynamic atmospheric phenomena such as clouds or storms.

“This finding serves as a significant benchmark for testing brown dwarf formation theories and atmospheric models,” the astronomers noted.

“Future spectroscopic studies may enable researchers to map the weather patterns on this intriguing object.”

“This achievement highlights the efficacy of combining ground-based and space-based observatories in discovering hidden worlds beyond our solar system.”

The team’s paper was published in Astronomy Magazine.

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Taichi Uyama et al. 2025. Direct Image Exploration for Companions with Subaru/IRD Strategic Program II. A brown dwarf companion star was discovered around the nearby medium-M dwarf LSPM J1446+4633. A.J. 170, 272; doi: 10.3847/1538-3881/ae08b6

Source: www.sci.news

Webb Discovers Biosignature Gas Phosphine in the Atmospheres of Ancient Brown Dwarfs

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Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have identified phosphine (PH)3 in the atmosphere of the brown dwarf Wolf 1130c, part of the triple system 1130ABC.

Schematic diagram of the Wolf 1130ABC triple system, featuring red dwarf star Wolf 1130a (left), compact white dwarf companion 1130b (center), and distant brown dwarf Wolf 1130c (right); each component scaled according to its relative size. Image credit: Adam Burgasser.

Wolf 1130ABC is located approximately 54 light years away in the constellation Cygnus.

The system is also known for LHS 482, Gliese 781, and Ross 1069b. It consists of three components: the Cool Red Star Wolf 1130a, the massive white dwarf Wolf 1130b, and the brown dwarf Wolf 1130c.

Initially discovered in 2013, Wolf 1130c orbits the closely bound systems of Wolf 1130a and Wolf 1130b on a wide trajectory.

“The astronomical initiative known as the Ancient Arcana concentrates on ancient, metal-rich brown dwarfs to enhance our understanding of atmospheric chemistry,” stated Adam Burgasser, a professor at the University of California, San Diego.

“Identifying phosphine was one of our primary objectives.”

Phosphine naturally emerges in the hydrogen-dominated atmospheres of gas giants like Jupiter and Saturn.

This has led scientists to theorize that phosphine should exist in the atmospheres of exoplanetary gas giants as well.

Nevertheless, previous Webb observations often failed to detect phosphines, pointing to an incomplete understanding of phosphorus chemistry.

“Before Webb, the expectation was that phosphine would be plentiful in planetary and brown dwarf atmospheres, according to theoretical models based on the turbulent mixing in these environments.”

Wolf 1130c is of particular interest to brown dwarf astronomers due to its lower concentration of “metals” (elements beyond hydrogen and helium) compared to the Sun.

In contrast to other brown dwarfs, the team successfully detected phosphines in the infrared spectral data collected by Webb from Wolf 1130c.

To accurately interpret their findings, researchers needed to ascertain the abundance of this gas within the atmosphere of Wolf 1130c.

“We employed a modeling approach called atmospheric recovery to quantify the molecular constituents of Wolf 1130c,” explained Dr. Irene Gonzalez from San Francisco State University.

“This technique leverages Webb’s data to validate the expected presence of various molecular gas species in the atmosphere.”

“It’s akin to reverse-engineering a delicious cookie when a chef remains committed to a recipe.”

“Typically, phosphorus may bond with other molecules, such as phosphorus trioxide,” remarked Dr. Baylor.

“In the metal-poor atmosphere of Wolf 1130c, insufficient oxygen prevents phosphorus from forming this way, allowing it to arise from phosphine-rich hydrogen.”

Alternatively, the phosphine could have been synthesized locally within the Wolf 1130ABC system, particularly from the white dwarf Wolf 1130b.

“The white dwarf represents the remnant shell of a star that has completed hydrogen fusion,” Professor Burgasser explained.

“These stars are incredibly dense and can accumulate material on their surfaces, potentially spurring runaway nuclear reactions.”

While astronomers have not observed such phenomena in the Wolf 1130ABC system in recent history, nova events usually cycle every thousands to tens of thousands of years.

This system has been recognized for just a century, and earlier invisible explosions may have contributed to a legacy of phosphorus contamination.

Gaining insights into why this particular brown dwarf exhibits a distinct signature of phosphine could shed new light on phosphorus synthesis in the Milky Way and atmospheric chemistry on exoplanets.

“If we aim to use this molecule in the quest for life in terrestrial worlds outside our solar system, understanding the atmospheric phosphine chemistry of brown dwarfs becomes crucial,” Professor Burgasser commented.

This study will be published in the journal Science.

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Adam J. Burgasser et al. Observation of unexpected phosphines in the atmosphere of the cold brown dwarf. Science. Released online on October 2, 2025. doi:10.1126/science.adu0401

Source: www.sci.news

Webb Discovers Auroras Using Free-Floating Brown Dwarfs

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Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have found evidence of energy deposition in the upper atmosphere of the nearby brown dwarf SIMP J013656.5+093347.3 caused by auroras.

Artist’s impression of aurora and brown dwarf SIMP-0136. Image credit: Evert Nasedkin.

SIMP J013656.5+093347.3 (commonly referred to as SIMP-0136) is a low-mass brown dwarf located 20 light years away in the Pisces constellation, approximately 6.12 light years from Earth.

As part of the Carina-near Stellar Association, this celestial object is estimated to be around 200 million years old.

The mass of SIMP-0136 is roughly estimated to fall between 12.7 and 17.8 times that of Jupiter.

With a spectral type of T2.5 and a temperature nearing 1,100 K, it exhibits many atmospheric properties similar to those of directly imaged exoplanets, such as HR 8799B and AF Lep b.

“Our observations have illuminated the activity of the robust aurora of SIMP-0136, which warms its atmosphere, much like the auroras on Earth and the powerful auroras found on Jupiter.”

“These measurements represent some of the most precise assessments of the atmospheres of extreme objects to this date, with direct measurements of atmospheric changes occurring for the first time.”

“Furthermore, with temperatures exceeding 1,500 degrees Celsius, SIMP-0136 will display mild heat waves this summer.”

“Our specific observations indicated that we could precisely record temperature variations of less than 5 degrees Celsius.”

“These temperature fluctuations were linked to minor alterations in the chemical makeup of this free-floating planet, hinting at storms akin to the Great Red Spot on Jupiter.

Another unexpected finding was the constancy of cloud variability in SIMP-0136.

Changes in cloud coverage might typically lead to atmospheric changes, similar to the variability observed with patches of clouds and clear skies on Earth.

However, astronomers discovered that cloud coverage remains stable across the surface of SIMP-0136.

At SIMP-0136’s temperatures, these clouds are distinct from Earth’s, primarily composed of silicate grains reminiscent of beach sand.

“Different wavelengths of light are associated with various atmospheric features,” stated Dr. Nasedkin.

“Similar to observing color changes on Earth’s surface, the color variations of SIMP-0136 are driven by alterations in atmospheric properties.”

“Utilizing advanced models enables us to deduce atmospheric temperature, chemical composition, and cloud positioning.”

“This work is thrilling as it showcases that by leveraging cutting-edge modeling techniques on Webb’s advanced datasets, we can understand the processes driving global weather throughout our solar system.”

“Understanding these meteorological processes is crucial as we continue discovering and characterizing exoplanets in the future.”

“Currently, such spectroscopic variability observations are limited to isolated brown dwarfs, but large telescopes and future studies, along with the eventual establishment of a habitable world observatory, will allow us to explore the atmospheric dynamics of exoplanets ranging from gas giants like Jupiter to rocky planets.”

The team’s survey results will be published in the journal Astronomy and Astrophysics.

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E. Nasedkin et al. 2025. JWST Weather Report: Investigating temperature variations, aurora heating, and stable cloud coverage on SIMP-0136. A&A 702, A1; doi: 10.1051/0004-6361/202555370

Source: www.sci.news

Astronomers Discover Rare Cloud-Forming Chemicals in Ancient Brown Dwarfs Dating Back a Billion Years

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Utilizing data gathered by NSF’s Gemini South Telescope and NASA/ESA/CSA James Webb Space Telescope, astronomers have identified methane signatures (CH4), water (H2O), and silane (SiH4) in the cold brown dwarf gas WISEA J153429.75-104303.3 (shortened to W1534). Silanes are predicted to act as significant reservoirs of silicon, the element responsible for the large clouds of gas that surround giant worlds, but their presence had remained undetected until now, masked by the development of deep silicate clouds in the observable atmosphere.

This artist’s illustration depicts a brown dwarf with an atmosphere filled with gas and dust clouds. Image credits: Noirlab/NSF/Aura/R. Proctor.

The W1534, referred to as the accident, is situated approximately 50 light years from Earth in the Libra constellation.

This brown dwarf was likely formed between 100 and 120 billion years ago and ranks among the oldest brown dwarfs discovered to date.

First identified in 2020 by citizen scientists participating in the Backyard Worlds: Planet 9 Citizen Science Project, its unusual light profile captivated astronomers.

Using two of the world’s most advanced terrestrial and space-based telescopes, astronomers examined its atmosphere to analyze its properties and composition.

The survey commenced with NSF’s Noirlab Astronomer Sandy Leggett capturing near-infrared images of W1534 with a Gemini South telescope in Chile, part of the International Gemini Observatory.

This initial work laid the groundwork for further explorations using Webb, guided by Noirlab Astronomer Aaron Meisner.

“W1534 is quite faint, and Gemini South is the only ground-based telescope capable of detecting it,” Dr. Meisner stated.

“The Gemini discovery paved the way for Webb’s observations by revealing the deeper atmospheric layers of this mysterious object and enabling us to determine the exposure time necessary to gather useful near-infrared data on its composition.”

Within W1534’s atmosphere, the team uncovered the crucial signature of silane, a compound formed from silicon and four hydrogen atoms.

Planetary scientists have long theorized the existence of this molecule within gas giants, attributing potential significance to its role in cloud formation within the atmosphere.

Despite extensive searches, its atmospheric presence has remained elusive in our solar system’s gas giants, Jupiter and Saturn, although thousands of studies on brown dwarfs and gas giants orbiting other stars have occurred.

This marks the first discovery of silanes in any brown dwarf, exoplanet, or solar system object.

The absence of this molecule in all but one singular brown dwarf suggests intriguing insights into the chemistry occurring in such an ancient environment.

“Often, it is these extreme objects that help us understand the average,” remarked Dr. Jackie Faherty, a researcher at the American Museum of Natural History.

The presence of silanes in W1534’s atmosphere implies that in very ancient objects, silicon is capable of bonding with hydrogen to form lighter molecules that can ascend to the upper layers of a gas giant’s atmosphere.

In contrast, more recently formed objects, such as Jupiter and Saturn, result in silicon bonding with readily available oxygen, producing heavier molecules that settle deeper into the atmospheric layers.

The evidence gleaned from W1534’s atmosphere further validates astronomers’ comprehension of gas giant cloud formation and sheds light on how primitive conditions influence atmospheric composition.

Moreover, it indicates that worlds formed billions of years ago display characteristics distinctly different from those formed during the early solar system.

“The formation and detection of silanes highlight an essential relationship among composition, cloud formation, and atmospheric mingling in cold brown dwarfs and planetary atmospheres,” the authors concluded.

Their paper is published in the journal Nature.

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jk faherty et al. 2025. A silicate precursor silane detected in cold, low-metallic brown dwarfs. Nature 645, 62-66; doi:10.1038/s41586-025-09369-1

Source: www.sci.news

Can Exoplanets Orbiting TRAPPIST-1 and Other Red Dwarfs Support Life?

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A protective atmosphere, a welcoming sun, and abundant liquid water make Earth a remarkable place. Leveraging the extraordinary capabilities of the NASA/ESA/CSA James Webb Space Telescope, astronomers are on a mission to uncover just how unique and extraordinary our planet truly is. Is it possible for a temperate environment to exist elsewhere, perhaps around a different type of star? The TRAPPIST-1 system offers an intriguing opportunity to explore this question, as it contains seven Earth-sized planets orbiting red dwarf stars—the most common type in the Milky Way.

The artist’s concept depicts TRAPPIST-1d passing in front of a turbulent star, showing the other planets in the background. Image credits: NASA/ESA/CSA/Joseph Olmsted, STSCI.

TRAPPIST-1 is a super cool dwarf star situated 38.8 light-years away in the constellation Aquarius.

These stars are slightly larger than Jupiter, comprising only 8% of our Sun’s mass. They rotate quickly and emit UV energy flares.

TRAPPIST-1 is home to seven transiting planets designated TRAPPIST-1b, c, d, e, f, g, and h.

All these planets are similar in size to Earth and Venus, or marginally smaller, with very brief orbital periods of 1.51, 2.42, 4.04, 6.06, 9.21, 12.35, and 20 days, respectively.

They may all be tidally locked, meaning the same side always faces their star, akin to how the same side of the moon is always turned towards Earth. This results in a permanently night side and a permanently day side for each TRAPPIST-1 planet.

“Ultimately, we aim to discover whether similar environments to those we enjoy on Earth exist elsewhere, and under what conditions they might thrive,” stated Dr. Caroline Piaulett Graeb, an astronomer at the University of Chicago and the Trottia Institute for Planetary Research.

“At this stage, we can exclude TRAPPIST-1d as a potential twin or cousin of Earth, even as Webb enables us to investigate Earth-sized planets for the first time.”

Dr. Piaulet-Ghorayeb and her team utilized Webb’s NIRSpec (near-infrared spectroscopy) instrument to capture the transmission spectra of the TRAPPIST-1d planet.

They found no common molecules typically present in Earth’s atmosphere, such as water, methane, or carbon dioxide.

However, they have outlined several possibilities for the exoplanet that warrant further investigation.

“There are multiple reasons we might not detect an atmosphere around TRAPPIST-1d,” Dr. Piaulet-Ghorayeb mentioned.

“It may have a very thin atmosphere, similar to Mars, which is challenging to identify.”

“Alternatively, thick, high-altitude clouds may obscure certain atmospheric signatures.”

“Or it could be a barren rock with no atmosphere whatsoever.”

In any case, TRAPPIST-1d faces challenges as a planet orbiting a red dwarf star.

TRAPPIST-1, the host star of the system, is known for its volatility and often emits high-energy radiation flares that can strip away the atmosphere of nearby small planets.

Nevertheless, scientists remain eager to search for atmospheric signs on the TRAPPIST-1 planets, as red dwarfs are the most prevalent stars in our galaxy.

If these planets can retain an atmosphere here, it suggests they could potentially do so anywhere, even under the harsh conditions of stellar radiation.

“Webb’s sensitive infrared instruments allow us to probe into the atmospheres of these small, cold planets for the first time,” said Dr. Bjorn Beneke, an astronomer at the Institute for Planetary Research at Montreal University.

“We are using Webb to identify atmospheres on Earth-sized planets and define the thresholds between those that can and cannot sustain an atmosphere.”

Results will be published in Astrophysical Journal.

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Caroline Piaulett Graeb et al. 2025. Restrictive conditions on the potential secondary atmosphere of the temperate rocky exoplanet TRAPPIST-1d. APJ 989, 181; doi:10.3847/1538-4357/ADF207

Source: www.sci.news

Dark Dwarfs Could Uncover the True Nature of Dark Matter

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A research team from Durham University, the University of Hawaii, and the University of Liverpool suggests that dark dwarfs are theoretical objects driven by dark matter, created from the cooling process of brown dwarfs.

An AI representation of a dark dwarf. Image credit: Gemini AI.

Currently, we understand that dark matter exists and how it behaves, but we are still unsure of its true nature.

In the last half-century, various theories have emerged, but gathering sufficient experimental evidence remains a challenge.

Some of the most well-known candidates for dark matter include weakly interacting massive particles (WIMPS), which are substantial particles that interact very slightly with ordinary matter. They pass through unnoticed, do not emit light, and reveal themselves only through gravitational effects.

This form of dark matter is essential for the existence of dark dwarfs.

“Dark matter interacts with gravity, allowing it to be captured by stars and accumulate within them,” explained Professor Jeremy Sachstein from the University of Hawaii.

“If this occurs, it may also interact internally, leading to annihilation and energy release that heats the star.”

A nuclear fusion process occurs at the star’s core, generating significant heat and energy, which allows a typical star to shine.

Fusion happens when a star’s mass is sufficient for gravity to compress matter toward the center intensely enough to initiate reactions between the nuclei.

This process releases a tremendous amount of energy, which is perceived as light. Although dark dwarfs also emit light, they do not do so through nuclear fusion.

“Dark dwarfs are low-mass objects, roughly 8% of the solar mass,” noted Professor Sachstein.

“Such small masses are insufficient to trigger a fusion reaction.”

“Consequently, these objects are prevalent in the universe but typically emit only dim light, being classified as brown dwarfs by scientists.

However, if brown dwarfs reside in regions with a high concentration of dark matter (such as the center of the Milky Way), they can evolve into different entities.

“These objects gather dark matter that enables them to transform into dark stars,” Professor Sachstein stated.

“The greater the surrounding dark matter, the more can be captured.”

“And as the dark material accumulates within the star, more energy is generated through its annihilation.”

“For a dark dwarf to exist, dark matter must consist of heavy particles that engage strongly with one another to produce visible matter.”

“Alternative candidates proposed to explain dark matter, such as axions, ambiguous ultralight particles, or sterile neutrinos, are too light to yield the expected effects on these objects.”

“Only massive particles capable of interacting with each other and annihilating to produce visible energy can facilitate the emergence of dark dwarfs.”

However, this hypothesis lacks substantial value without a definitive method of identifying dark dwarfs.

Therefore, Professor Sachstein and his team have suggested distinctive markers.

“There were a few indicators, but lithium-7 presents a unique scenario,” Professor Sachstein mentioned.

“Lithium-7 combusts readily and is rapidly depleted in regular stars.”

“Thus, if you identify an object resembling a dark dwarf, you should search for the presence of lithium, as it would be absent if it were a brown dwarf or something similar.”

The team’s study will be published in Journal of Cosmology and Astroparticle Physics.

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DJUNA CROON et al. 2025. Dark Dwarf: A theoretical dark matter-driven star-like object awaiting discovery at the Galactic Center. jcap 07:019; doi:10.1088/1475-7516/2025/07/019

Source: www.sci.news

Webb’s study highlights brown dwarfs in the fire nebula

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Astronomers using the NASA/ESA/CSA James Webb Space Telescope investigated the lowest mass limits of brown dwarfs within Flame Nebula, a hotbed of star formation in Orion’s constellation.

A collage of this image from the Flame Nebula shows a view of near-infrared light from Hubble on the left, while the two insets on the right show the near-infrared view taken by Webb. Image credits: NASA/ESA/CSA/M. Meyer, University of Michigan/A. Pagan, Stsci.

Flame Nebula It is about 1,400 light years away from Orion’s constellation.

Also known as NGC 2024 and SH2-277, this ejection nebula is about 12 light years wide and is less than a million years.

The Flame Nebula was discovered on January 1, 1786 by British astronomer William Herschel, born in Germany.

It is part of the Orion molecular cloud complex and includes famous nebulae such as the Hosehead Nebula and the Orion Nebula.

In a new study, astronomers used Webb to explore the lowest mass limits of brown dwarfs within the flame nebula.

The results, they found, were free-floating objects with mass about 2-3 times the mass of Jupiter.

“The goal of this project was to explore the fundamental low-mass limits of the star- and brown dwarf formation process,” said Dr. Matthew De Julio, an astronomer at the University of Texas at Austin.

“Webb allows you to investigate the faintest and lowest mass objects.”

The low mass limits that the required teams are looking for are set by a process known as fragmentation.

In this process, the large molecular clouds that produce both star and brown dwarfs are broken down into smaller units or fragments.

Fragmentation relies heavily on several factors where temperature, thermo-pressure, and gravity balance are the most important.

More specifically, as fragments contract under gravity, their cores become hot.

If the core is large enough, the hydrogen starts to fuse.

The outward pressure created by that fusion counters gravity, stops collapse and stabilizes the object.

However, the core is not compact, it is hot enough to burn hydrogen, and continues to shrink as long as it emits internal heat.

This near-infrared image of a portion of the Webb flame nebula highlights three low-mass objects found in the right inset. Image credits: NASA/ESA/CSA/STSCI/M. MEYER, University of Michigan.

“We’ve seen a lot of effort into making it,” said Dr. Michael Meyer, an astronomer at the University of Michigan.

“If the clouds cool efficiently, they collapse and fall apart.”

When the fragment becomes opaque enough to reabsorb its own radiation, fragmentation stops, thereby stopping cooling and preventing further decay.

The theory places the lower bounds of these fragments between 1-10 Jupiter masses.

This study significantly reduces its scope as the Webb census counted fragments of different masses within the nebulae.

“As we found in many previous studies, going to a lower mass actually increases the amount of objects about ten times as much as Jupiter’s mass,” Dr. Deirio said.

“Studies using Webb are sensitive to Jupiter up to 0.5 times the mass of Jupiter, and as they get below 10 times the mass of Jupiter, there are considerably fewer.”

“We discovered that there are fewer 5 Jupiter Mass objects than the Ten Jupiter Mass object, and we can see that there are fewer 3 Jupiter Mass objects than the 5 Jupiter Mass objects.”

“We don’t actually find any objects below the mass of two or three Jupiter. We’re hoping to see if they’re there, so we’re assuming this could be the limit itself.”

“For the first time, Webb was able to investigate beyond that limit,” added Dr. Meyer.

“If that limitation is real, there really is no object of 1 Jupiter mass that floats freely in our Milky Way galaxies, unless it forms as a planet and is kicked out of the planetary system.”

a paper Regarding the survey results, Astrophysics Journal Letter.

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Matthew de Julio et al. 2025. Identification of sales in the initial mass function of young star clusters up to 0.5 mJ. apjl 981, L34; doi: 10.3847/2041-8213/ADB96A

Source: www.sci.news

Cooler White Dwarfs Found to Have Less Bulge than Hotter Counterparts in Recent Study

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Using a catalog of 26,041 white dwarfs observed by the Sloan Digital Sky Survey, astronomers confirmed a long-predicted effect in these ancient, ultra-dense stars.

Concept art of two white dwarfs with the same mass but different temperatures. The hot star (left) is slightly swollen, while the cool star (right) is more compact. Image credit: Roberto Molar Candanosa / Johns Hopkins University.

At the end of their stellar evolution, stars that are not massive enough to become neutron stars or black holes eject their outer layers and leave their cores as compact remnants known as white dwarfs.

All stars with initial masses in the range of 0.07 to 8 solar masses (about 97% of all stars) end their lives as white dwarfs.

Dr Nicole Crumpler said: 'White dwarfs are a great way for us to work together to test theories underlying commonplace physics in the hope that we might discover something exotic that points to new fundamental physics. It is one of the best characterized stars ever made.” , an astrophysicist at Johns Hopkins University.

“If you want to look for dark matter, quantum gravity, and other unusual things, you need to have a good understanding of normal physics.”

“Otherwise, what seems novel may just be a new manifestation of an effect we already know.”

The new study was based on measurements of how these extreme conditions affect the light waves emitted by white dwarf stars.

As light moves away from such a huge object, it loses energy in the process of escaping gravity and gradually turns red.

This redshift effect stretches light waves like a rubber band so they can be measured with telescopes.

This is caused by the distortion of space-time caused by extreme gravity, as predicted by Einstein's theory of general relativity.

By averaging measurements of a white dwarf's motion with respect to Earth and grouping them according to gravity and size, astronomers can isolate gravitational redshifts to determine how high temperatures affect the volume of their gaseous outer layers. We measured the impact it had.

The team's 2020 study of 3,000 white dwarfs confirmed that electron degeneracy pressure causes stars to shrink as their mass increases. Electron degeneracy pressure is a quantum mechanical process that keeps dense nuclei stable for billions of years without the need for the nuclear fusion that normally underpins our sun and other planets. Types of stars.

“Until now, we haven't had enough data to confidently confirm the subtle but important effects of increasing temperature on the mass-size relationship,” Crumpler said.

“The next frontier may be detecting very subtle differences in the chemical composition of the cores of white dwarf stars of different masses,” said Dr. Nadia Zakamska, an astrophysicist at Johns Hopkins University.

“The maximum mass a star can have to form a white dwarf, as opposed to a neutron star or a black hole, is not completely understood.”

“These increasingly precise measurements will help test and refine theories about this and other poorly understood processes in the evolution of massive stars.”

“This observation could also help in attempts to discover signatures of dark matter, such as axions and other hypothetical particles,” Crumpler said.

“By providing a more detailed picture of the structure of white dwarfs, these data could be used to reveal the signals of certain models of dark matter that cause interference patterns in our galaxy.”

“If two white dwarfs are in the same dark matter interference patch, the dark matter will change the structure of these stars in the same way.”

Although dark matter has gravity, it does not emit light or energy that can be seen with telescopes.

Scientists have learned that the sun makes up most of the matter in the universe because its gravity affects stars, galaxies, and other space objects in the same way that it affects the orbits of planets. I am.

“We've been banging our heads against the wall trying to figure out what dark matter is, and I'd say we've been caught flat-footed,” Crumpler said.

“We know a lot about what dark matter is not, and there are limits to what dark matter can and cannot do, but we still don't know what it is.”

“That's why it's so important to understand simple objects like white dwarfs, because they give us hope of discovering what dark matter is.”

of study will appear in astrophysical journal.

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Nicole R. Crumpler others. 2024. Detection of temperature dependence of mass radius and gravitational redshift of white dwarfs. APJ 977, 237;doi: 10.3847/1538-4357/ad8ddc

Source: www.sci.news