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Images of Giant Exoplanet Candidates in Alpha Centauri’s Habitable Zone

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The planetary candidate, Alpha Centauri AB, may be a gas giant orbiting at a distance of one to two times that of the Earth from the Sun, as indicated in two research papers. Astrophysics Journal Letter. If verified, this planet would be the closest known to Earth within the habitable zone of a Sun-like star. Nonetheless, since it is a gas giant, astronomers do not believe it could support life as we understand it.

Artist’s rendering of the gas giant Alpha Centauri A. Image credits: NASA/ESA/CSA/STSCI/Robert L. Hurt, Caltech & IPAC.

Alpha Centauri resides in the Centaurus constellation and represents the nearest star system to Earth.

Also referred to as Rigil Centaurus, Rigil Kent, and Griese 559, this system includes a bright binary star pair, Alpha Centauri A and Alpha Centauri B, alongside a fainter red star known as Alpha Centauri C.

The two prominent stars are approximately 4.35 light-years away, while Alpha Centauri C, commonly called Proxima Centauri, is slightly nearer at about 4.23 light-years.

In comparison to the Sun, Alpha Centauri A is a G2-type star similar in nature, but slightly larger (1.1 times the size of the Sun and around 1.5 times its luminosity).

Alpha Centauri B, classified as a K1-type star, is slightly smaller and less luminous (approximately 0.9 times the mass of the Sun, with about 45% of its visual brightness).

These two stars orbit around a common center of gravity approximately every 80 years, maintaining a minimum distance of about 11 times that of the Earth-Sun distance.

Astronomers study these stars closely along with our nearest interstellar neighbor, Proxima Centauri, making them prime targets in the search for potentially habitable planets.

“This proximity offers the best chance to gather data on planetary systems beyond our own,” stated Dr. Charles Beichman from NASA’s Jet Propulsion Laboratory and the Exoplanet Science Institute at IPAC Astronomy Center in California.

“However, the brightness and swift motion of these stars present significant challenges in observation, even for the world’s most advanced space telescopes.”

The Alpha Centauri star system captured by different terrestrial and space-based observatories: DSS, Hubble Space Telescope, and James Webb Space Telescope. While the DSS shows the triple system as one light source, Hubble distinguishes between Alpha Centauri A and B. Webb’s Milimask image mitigates glare from Alpha Centauri A via a coronagraphic mask. Image credits: NASA/ESA/CSA/ANIKET SANGHI, CALTECH/CHAS BEICHMAN, NEXSCI, NASA & JPL-CALTECH/DIMITRI MAWET, CALTECH/JOSEPH DEPASQUALE, STSCI.

The first observations of this system occurred in August 2024, employing a Coronagraphic Mask with Webb’s Mid-Infrared Instrument (MIRI) to reduce the brightness of Alpha Centauri A.

The presence of nearby companion star Alpha Centauri B added complexity to the analysis, but astronomers successfully subtracted the light from both stars, uncovering objects that were more than 10,000 times dimmer than Alpha Centauri A.

On the other hand, an initial detection was promising, but further data was required for a definitive conclusion.

However, subsequent observations in February and April of 2025 did not unveil any objects akin to those detected in August 2024.

“We are facing a case of disappearing planets,” remarked Dr. Aniket Sangi from Caltech.

“To unravel this mystery, we employed computer models simulating millions of potential orbits, taking into account the insights gained from observing planets and their absence.”

In the simulations, the team incorporated the 2019 sightings of potential exoplanet candidates reported by the ESO’s Very Large Telescope, alongside new data from Webb, considering the gravitational stability of orbits influenced by Alpha Centauri B.

“The non-detections in the second and third rounds with Webb were not unexpected,” stated Sangi.

“In many simulated orbits, the planet was positioned too close to the star, rendering it invisible to Webb during both February and April 2025.”

“Based on mid-infrared observations of planetary brightness and orbital simulations, this gas giant could have a mass similar to Saturn, orbiting Alpha Centauri A at a distance one to two times greater than that between the Sun and Earth.”

“If confirmed, the potential planets identified in Webb’s Alpha Centauri images will represent a significant milestone in exoplanet imaging efforts,” Sangi added.

“Of all directly imaged planets, this would be the closest star we have ever observed.”

“Moreover, it would be the nearest to our home, with gas giants in our solar system that are similar in temperature and age to Earth.”

“The mere existence of two closely separated star systems poses intriguing challenges to our understanding of planetary formation, survival, and evolution within chaotic environments.”

If substantiated by further observations, these findings could reshape the field of exoplanet science.

“This will become a pivotal object in exoplanet research, offering multiple opportunities for detailed characterization by Webb and other observatories,” Dr. Beichman concluded.

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Charles Beichman et al. 2025. The Neighbor World: Imaging a giant planet candidate, orbital and physical properties of CEN A, and habitable zones at the exozodiacal upper limit. ApJL in press; Arxiv: 2508.03814

Aniket Sangi et al. 2025. The Neighbor World: Imaging a giant planet candidate in the habitable zone of Cen A. II. Binary Star Modeling, Planetary and Exozodiacal Search, and Sensitivity Analysis. ApJL in press; Arxiv: 2508.03812

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Candidates Around Young Stars in VLT: Identification of Protoplanetary and Sub-Ceres Objects

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Using Enhanced Resolution Imagers and Spectrographs (ERIS) from ESO’s Very Large Telescope (VLT), two teams of astronomers have discovered a protoplanet candidate nestled within a spiral disk surrounding the young star HD 135344B.

This image depicts a spiral disk surrounding Young Star HD 135344b. The observations made using the Enhanced Resolution Imager and Spectrograph (ERIS) identified a candidate planet contributing to the spiral structure in the disk, marked by a white circle. Image credits: ESO/Maio et al.

“While we may never witness the formation of Earth, this is a significant finding,” says Francesco Maio, a doctoral researcher at the University of Florence in Italy and lead author of a paper published in the journal Astronomy and Astrophysics.

Maio and his colleagues identified protoplanet candidates in the surrounding protoplanetary disks of HD 135344b. This F8V star, approximately 11.9 million years old, is situated 135 parsecs (440 light-years) from the Sun, in the Lupus constellation.

The protoplanet is estimated to be twice the size of Jupiter, located at a distance from its host star comparable to that of Neptune from the Sun.

It has been observed maturing at the periphery of the protoplanetary disk as it evolves into a fully-fledged planet.

Similar protoplanets have been detected around other young stars, often exhibiting intricate features such as rings, gaps, and spirals.

Astronomers long suspected that these structures were sculpted by forming planets, clearing away material as they orbit their parent stars.

Until now, however, no one has identified a planet actively shaping these features.

In the discs of HD 135344B, previous observations of swirling spiral arms were made by another team using VLT’s Sphere instrument.

Yet prior observations did not find evidence of any planets forming within this disk.

Utilizing VLT’s ERIS instrument, Maio and his collaborators may have discovered their primary suspect.

They identified a planetary candidate located at the base of one of the spiral arms of the disk, aligning with theoretical predictions about potential planets responsible for such patterns.

“What marks this detection as potentially groundbreaking is our ability to directly observe the signal from the protoplanet, unlike many earlier observations,” he notes.

“This gives us greater confidence in the existence of this planet, as we can see the light it emits.”

This image illustrates possible sub-brown dwarf companions orbiting Young Star V960 Mon. Candidate objects were detected using ESO’s Very Large Telescope (VLT) and the new Enhanced Resolution Imager and Spectrograph (ERIS). The ERIS data is shown in orange, overlaid with prior dusty disk images from VLT’s Sphere instruments (yellow) and ALMA (blue). Image credits: ESO/A. Dasgupta/ALMA/ESO/NAOJ/NRAO/Weber et al.

In a separate study, Anuroop Dasgupta, a doctoral researcher at ESO and Diego Portales University, along with colleagues, observed another young star using the ERIS instrument. V960 is located 1637.7 parsecs (5,342 light-years) away in the Monoceros constellation.

Prior observations using Sphere equipment and large millimeter/sub-millimeter arrays (ALMA) revealed that the material orbiting V960 Mon is shaped into complex spiral arms.

These observations also indicated that large clumps of material around the star undergo gravitational instability, contracting and collapsing—each capable of forming a planet or larger body, thus fragmenting the material.

Dasgupta and his collaborators managed to identify a brown dwarf or sub-brown dwarf companion around V960 Mon.

“Using ERIS, we aimed to discover compact, bright fragments indicative of companions in the disk,” he explains. Their findings are detailed in a paper published in the Astrophysical Journal Letters.

“One potential companion object was found very close to one of the observed spiral arms in the Universe and in ALMA data.”

“This object could represent a planet or a brown dwarf—larger than a planet but lacking sufficient mass to shine like a star.”

“If confirmed, this companion could be the first clear identification of a planet or brown dwarf formed via gravitational instability.”

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F. Maio et al. 2025. Development of Protoplanet candidates embedded using VLT/ERIS on HD135344B disks. A&A 699, L10; doi:10.1051/0004-6361/202554472

Anuroop Dasgupta et al. 2025. VLT/ERIS observations for the V960 series: dust-embedded sub-brown dwarf objects formed by gravitational instability? ApJL 988, L30; doi: 10.3847/2041-8213/ade996

Source: www.sci.news

Webb Identifies Potential Saturn-Mass Candidates Around Young Star Twa 7

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Astronomers utilize the exceptional sensitivity of the Mid-infrared instrument (Miri) on the NASA/ESA/CSA James Webb Space Telescope to investigate exoplanets within the three-ring debris disks surrounding the 6.4 million-year-old star TWA 7.

This Webb/Miri image shows the exoplanet TWA 7b, comparable in mass to Saturn. Image credits: NASA/ESA/CSA/WEBB/AM LAGRANGE/M. ZAMANI, ESA & WEBB.

Debris disks, comprised of dust and rocky materials, can exist around both young and evolved stars, but they are more luminous and detectable around younger celestial bodies.

These disks are often identified by their visible rings and gaps, which are believed to be shaped by planets that form within them.

The star TWA 7 is a low-mass (0.46 solar mass) M-type star situated approximately 111 light-years away in the constellation of Antlia.

Also referred to as Ce Antilae or Tyc 7190-2111-1, it is part of the TW Hydra Association.

The nearly edge-on three-ring fragmented disks make TWA 7 an optimal target for Webb’s highly sensitive mid-infrared observations.

“Our observations indicate a strong candidate for the planet that influences the structure of the TWA 7 debris disk, located precisely where we anticipated finding a planet of this mass,” states Dr. En Marie Lagrange, an astronomer at the Observatoire de Paris-PSL.

On June 21, 2024, Dr. Lagrange and colleagues employed a coronagraph with Webb’s Miri instrument to effectively suppress the bright glare of the host star, uncovering faint nearby objects.

This method, known as high contrast imaging, enables astronomers to directly observe planets that would otherwise be obscured by the overwhelming light of their host stars.

After eliminating residual starlight through advanced image processing, a faint infrared source was detected near TWA 7, distinguishable from background galaxies or other solar system objects.

This source is located within one of the three dust rings previously identified around TWA 7 by earlier ground-based investigations.

Its brightness, color, distance from the star, and position within the ring align with theoretical expectations for a young, cold Saturn-mass planet that shapes the surrounding debris disks.

“They are also the most popular and highly skilled professionals,” remarked Dr. Matilde Marin, an astronomer at Johns Hopkins University and the Institute for Space Telescope Science.

The team’s preliminary analysis suggests that the object known as TWA 7B has a mass approximately 0.3 times that of Jupiter (about 100 times that of Earth) and may be a young, cold exoplanet with a temperature of 320 K (around 47°C).

Its positioning (approximately 52 AU from the star) corresponds with a gap in the disk, indicating a dynamic interaction between the planet and its surroundings.

Once corroborated, this discovery marks the first direct link between a planet and the structure of debris, offering initial observational insights into the Trojan disk.

“These findings underscore Webb’s capability to probe previously unobservable low-mass planets orbiting nearby stars,” the astronomer commented.

“Ongoing and future observations will seek to more accurately characterize candidates, investigate the state of their atmospheres, and enhance our understanding of planet formation in young systems and the evolution of disks.”

“This preliminary result represents an exciting new frontier where Webb sheds light on the discovery and characterization of exoplanets.”

These findings are detailed in a publication in the journal Nature.

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Lagrange et al. Evidence of sub-Jovian planets within the young TWA 7 disk. Nature Published online on June 25th, 2025. doi:10.1038/s41586-025-09150-4

Source: www.sci.news

Webb’s discovery of brown dwarf candidates hints at first wealthy population outside of the Milky Way

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Astronomers using the NASA/ESA/CSA James Webb Space Telescope detected a population of 64 brown dwarf candidates with masses ranging from 50 to 84 Jupiter masses in the star cluster NGC 602.

This image of NGC 602 includes data from Webb's NIRCam (near-infrared camera) and MIRI (mid-infrared instrument) instruments. Image credits: NASA / ESA / CSA / Webb / P. Zeidler / E. Sabbi / A. Nota / M. Zamani, ESA & Webb.

NGC602 is a very young star cluster, about 200,000 light-years away in the constellation Hydra, about 2 to 3 million years old.

Also known as ESO 29-43, this star resides in the wings of the Small Magellanic Cloud.

NGC 602's local environment closely resembles that of the early Universe, with very low abundances of elements heavier than hydrogen and helium.

The presence of dark clouds of dense dust and the fact that the cluster is rich in ionized gas also suggests the presence of an ongoing star formation process.

Together with the associated HII region N90, which contains clouds of ionized atomic hydrogen, this cluster provides a rare opportunity to examine star formation scenarios under conditions dramatically different from those in the solar neighborhood.

Using Webb, Dr. Peter Zeidler and his colleagues at AURA and ESA were able to detect 64 brown dwarf candidates in NGC 602. This is the first rich population of brown dwarfs to exist outside the Milky Way.

“It is possible to detect objects at such great distances only with incredible sensitivity and spatial resolution in the right wavelength range,” Dr. Zeidler said.

“This has never been possible and will remain impossible from the ground for the foreseeable future.”

“So far, about 3,000 brown dwarfs are known, and they all live in our galaxy,” said Dr. Elena Mangiavakas, also from AURA and ESA.

“This discovery highlights the ability to use both Hubble and Webb to study young star clusters,” said Dr. Antonella Nota, executive director of the International Space Science Institute.

“Hubble showed that NGC 602 hosts very young, low-mass stars, but only Webb can conclusively confirm the extent and significance of substellar mass formation in this cluster. Hubble and Webb are an amazingly powerful telescope duo!”

“Our results are very consistent with the theory that the mass distribution of objects below the hydrogen burning limit is simply a continuation of the stellar distribution,” Dr. Zeidler said.

“They seem to form the same way, they just haven't accumulated enough mass to become full stars.”

NSF astronomer Dr. Elena Sabbi said, “Studying the newly discovered metal-poor young brown dwarfs in NGC 602 will shed light on how stars and planets formed under the harsh conditions in the early universe. We are getting closer to uncovering the secrets of this.” NOIRLab, University of Arizona, Space Telescope Science Institute.

“These are the first substellar objects outside the Milky Way,” Manjavakas said.

“We need to be prepared for new breakthrough discoveries in these new objects.”

of result will appear in astrophysical journal.

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peter zeidler others. 2024. A candidate for a subsolar metallic brown dwarf is discovered in the Small Magellanic Cloud. APJ 975, 18; doi: 10.3847/1538-4357/ad779e

Source: www.sci.news

352 new binary asteroid candidates discovered by ESA’s Gaia mission

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Binary asteroid systems have attracted the attention of the scientific community due to their intriguing properties and significant impact on our understanding of the Solar System. Unlike single asteroids, binary systems provide unique insights into many fundamental processes, including planetary formation and evolution, collision dynamics, and gravitational interactions.

Gaia has discovered possible moons around 352 asteroids that are not known to have companion stars. Image courtesy of ESA.

Asteroids are fascinating celestial objects that hold unique insights into the formation and evolution of our solar system.

Binary stars are even more fascinating because they allow astronomers to study how different objects in the universe form, collide, and interact.

With our unique all-sky scanning function, ESA's Gaia satellite Since its launch in 2013, it has made a number of important asteroid discoveries.

In Data Release 3, Gaia pinpointed the positions and movements of more than 150,000 asteroids. That precision has allowed scientists to probe deeper, looking for asteroids that exhibit a characteristic “wobble” caused by the gravitational pull of their orbiting companion stars.

Gaia has also collected data on the asteroid's chemistry, compiling the largest ever collection of asteroid reflectance spectra – light curves that reveal an object's color and composition.

More than 150,000 orbits determined in Gaia's Data Release 3 were refined as part of the mission's Focused Product Release last year, making them 20 times more accurate.

Gaia's upcoming Data Release 4 (due after mid-2026) is expected to reveal the orbits of even more asteroids.

“Binary asteroids are difficult to find because most are very small and far away from Earth,” said Dr Luana Liberato, an astronomer at the Observatory of the Côte d'Azur.

“Although just under one in six asteroids are predicted to have companion stars, only half a billion of the one million known asteroids have been found to be in binary systems.”

“But this discovery shows that there are many more asteroid moons still waiting to be discovered.”

“If confirmed, this new discovery adds 352 potential binary systems, nearly doubling the known number of moon-bearing asteroids.”

“Gaia is proving to be an excellent asteroid explorer, working hard to unlock the secrets of the universe, both within our solar system and beyond,” said Dr Timo Prusti, ESA's Gaia project scientist.

“This discovery highlights the Gaia data release as a major improvement in data quality and demonstrates the incredible new science made possible by this mission.”

a paper A paper describing the results has been published in the journal Astronomy and Astrophysics.

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L. Liberato others2024. Binary asteroid candidate in the Gaia DR3 astronomical measurements. A&A 688, A50;doi: 10.1051/0004-6361/202349122

This article was based on an original release from ESA.

Source: www.sci.news