Free-Floating Exoplanets Are Growing at Unprecedented Rates

Cha J11070768-7626326 (shortened to Cha 1107-7626), a young and isolated exfoliating planet five to ten times the mass of Jupiter, has undergone a remarkable “growth spurt,” accumulating approximately 600 million tons of gas and dust within just a few months in the new sulse.

Artists’ impressions of Xplanet CHA 1107-7626 floating freely. Image credits: ESO/L. Kalsada/M. Kornmesser.

Located approximately 620 light years from the constellation Chamaeleon, Cha 1107-7626 is a free-floating exoplanet still in formation, drawing material from a gas and dust surrounding disc.

This material consistently falls onto planets, a process known as acquisition.

By August 2025, CHA 1107-7626 had increased its accretion rate to about eight times faster than just a few months prior, reaching an astonishing 6 billion tons per second.

“While it is often thought that planets are quiet and stable, this discovery shows that planetary mass objects drifting in space can be incredibly dynamic,” says Dr. Víctor Almendros-Abad.

“We have observed this newly forming illicit planet devouring material at a fierce pace,” remarked Ray Jayawardana, a professor at Johns Hopkins University.

“Our ongoing monitoring over recent months, utilizing two of the most powerful telescopes on Earth and in space, has provided us with rare insight into the infant stages of isolated objects not much larger than Jupiter.”

“Their early existence appears to be significantly more turbulent than previously conceived.”

“This represents the most intense accretion episode ever documented for planetary mass objects,” added Dr. Almendros-Abad.

The discovery was made using the X-Shooter spectrograph on the Very Large Telescope (VLT) operated by ESO in the Atacama Desert, Chile.

Astronomers also employed data from the NASA/ESA/CSA James Webb Space Telescope, as well as archived data from the SINFONI Spectrograph of the VLT.

“The origins of illicit planets remain an open question: are they the lowest mass objects that form like stars, or are they giant planets ejected from their birth systems?” queried Dr. Alex Scholz, an astronomer at St. Andrews University.

Results suggest that at least some illicit planets may follow formation pathways similar to stars, as analogous bursts have been previously observed in younger stellar bodies.

“This finding blurs the line between stars and planets, offering a glimpse into the earliest formation periods of these objects,” states Dr. Belinda Damien, an astronomer at St. Andrews University.

By comparing the light emitted before and after the burst, astronomers gathered insights into the nature of the accretion process.

Interestingly, magnetic activity seems to contribute to driving this intense process.

This indicates that even low-mass objects can possess strong magnetic fields capable of fueling such accretion events.

The team also discovered that the chemistry of the surrounding discs changes during accretion episodes, with water vapor detected in the steam.

This phenomenon has been noted in stars but not previously observed in any type of planet.

“We are beginning to understand how the early life of a free-floating planetary mass object resembles that of a sun-like star,” stated Professor Jayawardana.

“Our recent discoveries emphasize this similarity, suggesting that some giant planet-like objects may form in a manner akin to stars and experience growth episodes similar to newborn stars as they accumulate gas and dust with their own discs.”

The team’s paper was published today in the Astrophysics Journal Letter.

____

Victor Almendros-Abad et al. 2025. Discovery of accretion bursts on free-floating planetary mass objects. apjl 992, L2; doi: 10.3847/2041-8213/ae09a8

Source: www.sci.news

Webb Discovers Auroras Using Free-Floating Brown Dwarfs

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.

____

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

Webb finds six free-floating exoplanets in NGC 1333

How to use Near-infrared imaging device and slitless spectrometer Using the NIRISS instrument on the NASA/ESA/CSA James Webb Space Telescope, astronomers have discovered six new free-floating planet-mass members of NGC 1333, with estimated masses ranging from 5 to 15 times that of Jupiter. One of these objects is five times the mass of Jupiter (about 1,600 times that of Earth), making it likely the lowest-mass object with a dusty planetary orbiting disk.

NIRISS-NGC1333-5 (also known as NN5), with an estimated mass five times that of Jupiter, is the lowest-mass object yet found in NGC 1333 and is likely the lowest-mass object with a disk in any region identified so far. Image credit: Langeveld others., doi:10.3847/1538-3881/ad6f0c.

NGC 1333 is a star-forming cluster located about 1,000 light-years away in the northern constellation Perseus.

Also known as Ced 16 and LBN 741, the star cluster was first discovered in 1855 by German astronomer Eduard Schoenfeld.

NGC 1333 is only 1 to 3 million years old and harbors brown dwarfs equivalent to about half the number of stars, a higher proportion than previously observed.

“We're exploring the limits of the star formation process,” said astrophysicist Adam Langeveld of Johns Hopkins University.

“If we had a young Jupiter-like object, could it become a star under the right conditions? This is important context for understanding the formation of stars and planets.”

Dr. Langeveld and his colleagues used Webb's NIRISS instrument to carry out an extremely deep spectroscopic survey of NGC 1333.

Observations have discovered 19 known brown dwarfs and six free-floating planetary-mass objects with masses between 5 and 10 times that of Jupiter.

This means they are among the most lightweight objects yet discovered that were formed from processes that normally produce stars or brown dwarfs (objects that straddle the boundary between stars and planets, do not undergo hydrogen fusion reactions, and disappear over time).

“We used the Webb Telescope's unprecedented sensitivity at infrared wavelengths to search for the faintest members of young star clusters and answer a fundamental question in astronomy: how can objects form star-like shapes with light?” said Ray Jayawardene, an astrophysicist at Johns Hopkins University.

“The smallest stray objects forming like stars turn out to be comparable in mass to giant exoplanets orbiting nearby stars.”

Webb's observations, despite being sensitive enough to detect such objects, did not find any objects with a mass less than five times that of Jupiter.

This strongly suggests that stars less massive than this threshold are likely to form in the same way as planets.

“Our observations confirm that nature produces planetary-mass objects in at least two different ways: from the collapse of clouds of gas and dust as stars form, and from disks of gas and dust around young stars, such as Jupiter in our own solar system,” Dr Jayawardene said.

The most interesting of the planetary-mass objects is NIRISS-NGC1333-5, which is the lightest, with an estimated mass of five Jupiters.

“The presence of a dust disk means that the object almost certainly formed like a star, because cosmic dust typically revolves around a central object during the early stages of star formation,” Dr Langeveld said.

“Disks are also a prerequisite for planet formation, so our observations could also have important implications for potential small planets.”

“These small objects with masses comparable to the giant planets could potentially form planets themselves,” said Dr Alex Scholz, an astrophysicist at the University of St Andrews.

“This could be a nursery for small planetary systems, much smaller in scale than our solar system.”

Astronomers also discovered a new brown dwarf with a planetary-mass companion, a rare find that calls into question theories about how binary star systems form.

“Such pairs likely formed from a contracting, fragmenting cloud, much like a binary star system,” Dr Jayawardene said.

“The diversity of systems created by nature is astonishing and inspires us to refine our models of star and planet formation.”

of Survey results will be published in Astronomical Journal.

_____

Adam B. Langefeld others2024. JWST/NIRISS Deep Light Survey of Young Brown Dwarfs and Free-Floating Planets. AJin press; doi: 10.3847/1538-3881/ad6f0c

Source: www.sci.news

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

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.

_____

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

Webb finds small, free-floating brown dwarf in star-forming cluster IC 348

The newly discovered brown dwarf is estimated to have a mass three to four times that of Jupiter, making it a strong candidate for the lowest mass free-floating brown dwarf ever directly imaged.

This image from Webb’s NIRCam instrument shows the central portion of star cluster IC 348. Image credits: NASA / ESA / CSA / STScI / K. Luhman, Pennsylvania State University / C. Alves de Oliveira, ESA.

Brown dwarfs are cold, dark objects that are between the size of gas giant planets and Sun-like stars.

These objects, also known as failed stars, have star-like properties even though they are too small to sustain hydrogen fusion reactions in their cores.

Typically, their masses are between 11 and 16 Jupiter (the approximate mass that can sustain deuterium fusion) and 75 and 80 Jupiter (the approximate mass that can sustain hydrogen fusion).

“One of the basic questions you’ll find in any astronomy textbook is: What is the smallest star? That’s what we’re trying to answer,” said Kevin, an astronomer at Penn State University.・Dr. Luman said.

The newly discovered brown dwarf resides in IC 348, a star cluster 1,000 light-years away in the constellation Perseus.

The cluster, also known as Collinder 41, Gingrich 1, and Theia 17, contains nearly 400 stars and is about 5 million years old.

IC 348 is part of the larger Perseus star-forming region, and although it is normally invisible to the naked eye, it shines brightly when viewed at infrared wavelengths.

Dr. Luhmann and his colleagues used the following method to image the center of the star cluster. Webb’s NIRCam device Identify brown dwarf candidates based on their brightness and color.

They followed up on the most promising targets using: Webb’s NIRSpec microshutter array.

This process created three interesting targets with masses between three and eight Jupiters and surface temperatures between 830 and 1,500 degrees Celsius.

Computer models suggest that the smallest of these weighs just three to four times as much as Jupiter.

ESA astronomer Dr Catalina Alves de Oliveira said: “With current models, it is very easy to create a giant planet in a disk around a star.”

“But in this cluster, the object is unlikely to form as a disc, but instead as a star, with three Jupiters having a mass 300 times less than the Sun.”

“Then we have to ask how the star formation process takes place at such a very small mass.”

Two of the brown dwarfs identified by the research team exhibit spectral signatures of unidentified hydrocarbons, molecules that contain both hydrogen and carbon atoms.

The same infrared signature was detected in the atmospheres of Saturn and its moon Titan by NASA’s Cassini mission.

It has also been observed in the interstellar medium, the gas between stars.

“This is the first time this molecule has been detected in the atmosphere of an object outside our solar system,” Dr de Oliveira said.

“Models for brown dwarf atmospheres do not predict their existence. We are observing objects that are younger and have lower masses than ever before, and we are seeing something new and unexpected.” .”

a paper Regarding the survey results, astronomy magazine.

_____

KL Luman other. 2023. JWST survey of planetary mass brown dwarfs in IC 348. A.J. 167, 19; doi: 10.3847/1538-3881/ad00b7

Source: www.sci.news