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Small, compact galaxies seen in the early universe have puzzled astronomers – finding these unusual objects closer to home could provide hints about how they form

arXiv:2507.12622v1 Announce Type: new Abstract: Temperate sub-Neptunes are compelling targets for detecting liquid-water oceans beyond the Solar System. If water-rich and lacking massive hydrogen-helium envelopes, these planets could sustain liquid layers beneath their atmospheres despite sizes larger than Earth. Previous observations of the temperate sub-Neptune K2-18 b revealed an H2-dominated atmosphere rich in CH4, with moderate evidence for CO2 and tentative signs of dimethyl sulfide (DMS). Here we present four new JWST/NIRSpec transit observations of K2-18 b. The resulting high-precision transmission spectrum robustly detects both CH4 and CO2, precisely measuring their abundances and firmly establishing the planet's water-rich nature: either a thick envelope with >10% H2O by volume or a thin atmosphere above a liquid-water ocean. The spectrum reveals no detectable H2O, NH3, or CO. The absence of atmospheric water vapor suggests an efficient cold trap, while the nondetections of NH3 and CO support the scenario of a small H2-rich atmosphere overlying a liquid reservoir. However, alternative models that include these gases can also reproduce the spectrum within uncertainties, highlighting the need for deeper observations. The spectrum only contains marginal signals of DMS, methyl mercaptan (CH3SH), and nitrous oxide (N2O), with none exceeding 3 sigma in model preference and all falling below ~2 sigma without imposing a strong super-Rayleigh haze. Meanwhile, our self-consistent photochemical models show that DMS and CH3SH may form abiotically in massive H2-rich atmospheres of high metallicity, making it important to consider additional indicators for their potential use as biosignatures. K2-18 b, a cool, water-rich world, stands out as one of the most promising temperate sub-Neptunes for exploring the emergence of liquid-water environments in non-Earth-like planets, motivating further characterization of its atmosphere and interior.

arXiv:2507.12622v1 Announce Type: new Abstract: Temperate sub-Neptunes are compelling targets for detecting liquid-water oceans beyond the Solar System. If water-rich and lacking massive hydrogen-helium envelopes, these planets could sustain liquid layers beneath their atmospheres despite sizes larger than Earth. Previous observations of the temperate sub-Neptune K2-18 b revealed an H2-dominated atmosphere rich in CH4, with moderate evidence for CO2 and tentative signs of dimethyl sulfide (DMS). Here we present four new JWST/NIRSpec transit observations of K2-18 b. The resulting high-precision transmission spectrum robustly detects both CH4 and CO2, precisely measuring their abundances and firmly establishing the planet's water-rich nature: either a thick envelope with >10% H2O by volume or a thin atmosphere above a liquid-water ocean. The spectrum reveals no detectable H2O, NH3, or CO. The absence of atmospheric water vapor suggests an efficient cold trap, while the nondetections of NH3 and CO support the scenario of a small H2-rich atmosphere overlying a liquid reservoir. However, alternative models that include these gases can also reproduce the spectrum within uncertainties, highlighting the need for deeper observations. The spectrum only contains marginal signals of DMS, methyl mercaptan (CH3SH), and nitrous oxide (N2O), with none exceeding 3 sigma in model preference and all falling below ~2 sigma without imposing a strong super-Rayleigh haze. Meanwhile, our self-consistent photochemical models show that DMS and CH3SH may form abiotically in massive H2-rich atmospheres of high metallicity, making it important to consider additional indicators for their potential use as biosignatures. K2-18 b, a cool, water-rich world, stands out as one of the most promising temperate sub-Neptunes for exploring the emergence of liquid-water environments in non-Earth-like planets, motivating further characterization of its atmosphere and interior.

arXiv:2503.02291v3 Announce Type: replace Abstract: We present the SpecDis value added stellar distance catalog accompanying DESI DR1. SpecDis trains a feed-forward Neural Network (NN) with Gaia parallaxes and gets the distance estimates. To build up unbiased training sample, we do not apply selections on parallax error or signal-to-noise (S/N) of the stellar spectra, and instead we incorporate parallax error into the loss function. Moreover, we employ Principal Component Analysis (PCA) to reduce the noise and dimensionality of stellar spectra. Validated by independent external samples of member stars with precise distances from globular clusters (GCs), dwarf galaxies, stellar streams, combined with blue horizontal branch (BHB) stars, we demonstrate that our distance measurements show no significant bias up to 100kpc, and are much more precise than Gaia parallax beyond 7kpc. The median distance uncertainties are 23%, 19%, 11% and 7% for S/N $<$ 20, 20 $\leq$ S/N$<$ 60, 60 $\leq$ S/N $<$ 100 and S/N $\geq$ 100. Selecting stars with $\log g<3.8$ and distance uncertainties smaller than 25%, we have more than 74,000 giant candidates within 50kpc to the Galactic center and 1,500 candidates beyond this distance. Additionally, we develop a Gaussian mixture model to identify unresolvable equal-mass binaries by modeling the discrepancy between the NN-predicted and the geometric absolute magnitudes from Gaia parallaxes and identify 120,000 equal-mass binary candidates. Our final catalog provides distances and distance uncertainties for $>$ 4 million stars, offering a valuable resource for Galactic astronomy.

arXiv:2503.02291v3 Announce Type: replace Abstract: We present the SpecDis value added stellar distance catalog accompanying DESI DR1. SpecDis trains a feed-forward Neural Network (NN) with Gaia parallaxes and gets the distance estimates. To build up unbiased training sample, we do not apply selections on parallax error or signal-to-noise (S/N) of the stellar spectra, and instead we incorporate parallax error into the loss function. Moreover, we employ Principal Component Analysis (PCA) to reduce the noise and dimensionality of stellar spectra. Validated by independent external samples of member stars with precise distances from globular clusters (GCs), dwarf galaxies, stellar streams, combined with blue horizontal branch (BHB) stars, we demonstrate that our distance measurements show no significant bias up to 100kpc, and are much more precise than Gaia parallax beyond 7kpc. The median distance uncertainties are 23%, 19%, 11% and 7% for S/N $<$ 20, 20 $\leq$ S/N$<$ 60, 60 $\leq$ S/N $<$ 100 and S/N $\geq$ 100. Selecting stars with $\log g<3.8$ and distance uncertainties smaller than 25%, we have more than 74,000 giant candidates within 50kpc to the Galactic center and 1,500 candidates beyond this distance. Additionally, we develop a Gaussian mixture model to identify unresolvable equal-mass binaries by modeling the discrepancy between the NN-predicted and the geometric absolute magnitudes from Gaia parallaxes and identify 120,000 equal-mass binary candidates. Our final catalog provides distances and distance uncertainties for $>$ 4 million stars, offering a valuable resource for Galactic astronomy.

Science, Volume 389, Issue 6757, Page 222-223, July 2025.

Science, Volume 389, Issue 6757, Page 225-226, July 2025.

4 min read

NASA to Launch SNIFS, Sun’s Next Trailblazing Spectator

July will see the launch of the groundbreaking Solar EruptioN Integral Field Spectrograph mission, or SNIFS. Delivered to space via a Black Brant IX sounding rocket, SNIFS will explore the energy and dynamics of the chromosphere, one of the most complex regions of the Sun’s atmosphere. The SNIFS mission’s launch window at the White Sands Missile Range in New Mexico opens on Friday, July 18. 

The chromosphere is located between the Sun’s visible surface, or photosphere, and its outer layer, the corona. The different layers of the Sun’s atmosphere have been researched at length, but many questions persist about the chromosphere. “There’s still a lot of unknowns,” said Phillip Chamberlin, a research scientist at the University of Colorado Boulder and principal investigator for the SNIFS mission.  

The reddish chromosphere is visible on the Sun’s right edge in this view of the Aug. 21, 2017, total solar eclipse from Madras, Oregon.Credit: NASA/Nat Gopalswamy

The chromosphere lies just below the corona, where powerful solar flares and massive coronal mass ejections are observed. These solar eruptions are the main drivers of space weather, the hazardous conditions in near-Earth space that threaten satellites and endanger astronauts. The SNIFS mission aims to learn more about how energy is converted and moves through the chromosphere, where it can ultimately power these massive explosions.  

“To make sure the Earth is safe from space weather, we really would like to be able to model things,” said Vicki Herde, a doctoral graduate of CU Boulder who worked with Chamberlin to develop SNIFS.  

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This footage from NASA’s Solar Dynamics Observatory shows the Sun in the 304-angstrom band of extreme ultraviolet light, which primarily reveals light from the chromosphere. This video, captured on Feb. 22, 2024, shows a solar flare — as seen in the bright flash on the upper left.Credit: NASA/SDO

The SNIFS mission is the first ever solar ultraviolet integral field spectrograph, an advanced technology combining an imager and a spectrograph. Imagers capture photos and videos, which are good for seeing the combined light from a large field of view all at once. Spectrographs dissect light into its various wavelengths, revealing which elements are present in the light source, their temperature, and how they’re moving — but only from a single location at a time. 

The SNIFS mission combines these two technologies into one instrument.  

“It’s the best of both worlds,” said Chamberlin. “You’re pushing the limit of what technology allows us to do.” 

By focusing on specific wavelengths, known as spectral lines, the SNIFS mission will help scientists to learn about the chromosphere. These wavelengths include a spectral line of hydrogen that is the brightest line in the Sun’s ultraviolet (UV) spectrum, and two spectral lines from the elements silicon and oxygen. Together, data from these spectral lines will help reveal how the chromosphere connects with upper atmosphere by tracing how solar material and energy move through it. 

The SNIFS mission will be carried into space by a sounding rocket. These rockets are effective tools for launching and carrying space experiments and offer a valuable opportunity for hands-on experience, particularly for students and early-career researchers.

(From left to right) Vicki Herde, Joseph Wallace, and Gabi Gonzalez, who worked on the SNIFS mission, stand with the sounding rocket containing the rocket payload at the White Sands Missile Range in New Mexico.Credit: courtesy of Phillip Chamberlin

“You can really try some wild things,” Herde said. “It gives the opportunity to allow students to touch the hardware.” 

Chamberlin emphasized how beneficial these types of missions can be for science and engineering students like Herde, or the next generation of space scientists, who “come with a lot of enthusiasm, a lot of new ideas, new techniques,” he said. 

The entirety of the SNIFS mission will likely last up to 15 minutes. After launch, the sounding rocket is expected to take 90 seconds to make it to space and point toward the Sun, seven to eight minutes to perform the experiment on the chromosphere, and three to five minutes to return to Earth’s surface.  

A previous sounding rocket launch from the White Sands Missile Range in New Mexico. This mission carried a copy of the Extreme Ultraviolet Variability Experiment (EVE).
Credit: NASA/University of Colorado Boulder, Laboratory for Atmospheric and Space Physics/James Mason

The rocket will drift around 70 to 80 miles (112 to 128 kilometers) from the launchpad before its return, so mission contributors must ensure it will have a safe place to land. White Sands, a largely empty desert, is ideal. 

Herde, who spent four years working on the rocket, expressed her immense excitement for the launch. “This has been my baby.” 

By Harper Lawson
NASA’s Goddard Space Flight Center, Greenbelt, Md.

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Details Last Updated Jul 17, 2025 Related Terms

• Heliophysics
• Goddard Space Flight Center
• Heliophysics Division
• Science & Research
• Sounding Rockets
• Sounding Rockets Program
• Wallops Flight Facility

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We are seeking an experienced and enthusiastic Cloud Engineer to be based at the Institute of Astronomy (www.ast.cam.ac.uk) in collaboration with the Research Computing Services (www.hpc.cam.ac.uk) at the University of Cambridge. This role is part of a new and exciting initiative to develop the UK SKA Regional Centre, (UKSRC: www.uksrc.org) for the Square Kilometre Array Observatory (SKAO: www.skao.int), the world's largest radio telescope. You will join a diverse team working in collaboration with national and international colleagues to help develop, deliver and operate the UKSRC and international Network of SKA Regional Centres (SRCNet) cloud infrastructure and computing resources, as an integral part of the development of the SKA Observatory project (www.skao.int). The UKSRC project, benefits from contributions from the Universities of Cambridge, Durham, Edinburgh, Hertfordshire, London (UCL), Manchester and the UKRI STFC Scientific Computing Division.

The successful candidate will become part of a diverse team of systems engineers, research software engineers and data scientists, developing advanced solutions to support world-class science and via the delivery of configurable, robust distributed digital research infrastructure service for processing data, and supporting the scientific exploitation of observational data, obtained with the world's largest radio telescope running on a Kubernetes (K8s) open-souplatform. In addition, this role will have the opportunity to support the development of similar cloud-based infrastructure for the Cambridge Centre of Excellence in Astronomical Data (CamCEAD), based at the Institute of Astronomy to support a range of data-intensive ground and space-based imaging and spectroscopic missions and research projects.

Skills and Experience

Preferred:

• Hands on experience in deploying and administering Linux operating systems.
• Familiarity of Ansible & Terraform for configuration management & IAC.
• Experience of virtualization technologies and cloud architecture, preferably but not limited to OpenStack.
• Proven ability to work effectively within a team and individually.
• Basic knowledge of scripting languages primarily with Python & Bash.
• Experience of CI/CD principles, ideally but not essentially using a GitOps approach, using Helm & Kustomize.
• Software development lifecycle tools, such as Git.
• Working with Agile methodologies.

Desirable:

• Use of monitoring and reporting tools, such as Prometheus and Grafana.
• Experience of GitOps tooling such as ArgoCD or FluxCD.
• Knowledge of containerization technologies using Kubernetes & Docker.
• Experience working with HPC clusters and parallel file systems.
• Experience in working in a scientific environment and/or providing support to researchers.

More information about the role is attached in the 'Further Particulars' document.

The University is supportive of hybrid working. We aim to enable as many staff as possible to work in a hybrid way if they wish, and where their role allows. This role permits the post holder to be office based or hybrid, but to be in the office regularly when required, either at the IoA at Madingley Rise, or the Research Computing Service, in the Roger Needham Building.

Fixed-term: The funds for this post are available until 31 March 2027 in the first instance.

Once an offer of employment has been accepted, the successful candidate will be required to undergo a basic disclosure (criminal records check) check and a security check.

Conversations about flexible working are encouraged at the University of Cambridge. Please feel free to discuss flexibility prior to applying (using the contact information below) or at interview if your application is successful.

Click the 'Apply' button below to register an account with our recruitment system (if you have not already) and apply online.

Please upload your CV and cover letter in the Upload section of this application process. Names and contact details of 2 professional referees are essential. References will be requested for candidates following the application closing date and referees will be asked to complete references by the interview date where permission is given from the candidates to do so; such contact will be direct to your referees via our recruitment system.

Informal enquiries are welcomed and should be directed to Sean McConkey at sm2921@cam.ac.uk in the first instance, quoting reference number LG46639. If you have any queries regarding the application process, please contact: HR@ast.cam.ac.uk.

The closing date for applications is: 23:59 BST on 1st August 2025

The anticipated interview dates are: w/c 11th August 2025 and w/c 18th August 2025

We are seeking a start date ideally no later than 1 October 2025.

Please quote reference LG46639 on your application and in any correspondence about this vacancy.

The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.

The University has a responsibility to ensure that all employees are eligible to live and work in the UK.

arXiv:2506.14615v2 Announce Type: replace Abstract: Planetary systems orbiting close binaries are valuable testing grounds for planet formation and migration models. More detections with good mass measurements are needed. We present a new planet discovered during the BEBOP survey for circumbinary exoplanets using radial velocities. We use data taken with the SOPHIE spectrograph at the Observatoire de Haute-Provence, and perform a spectroscopic analysis to obtain high precision radial velocities. This planet is the first radial velocity detection of a previously unknown circumbinary system. The planet has a mass of $0.56$ $M_{Jup}$ and orbits its host binary in 550 days with an eccentricity of 0.25. Compared to most of the previously known circumbinary planets, BEBOP-3b has a long period (relative to the binary) and a high eccentricity. There also is a candidate outer planet with a $\sim1400$ day orbital period. We test the stability of potential further candidate signals inside the orbit of BEBOP-3b, and demonstrate that there are stable orbital solutions for planets near the instability region which is where the Kepler circumbinary planets are located. We also use our data to obtain independent dynamical masses for the two stellar components of the eclipsing binary using High Resolution Cross-Correlation Spectroscopy (HRCCS), and compare those results to a more traditional approach, finding them compatible with one another.

arXiv:2506.14615v2 Announce Type: replace Abstract: Planetary systems orbiting close binaries are valuable testing grounds for planet formation and migration models. More detections with good mass measurements are needed. We present a new planet discovered during the BEBOP survey for circumbinary exoplanets using radial velocities. We use data taken with the SOPHIE spectrograph at the Observatoire de Haute-Provence, and perform a spectroscopic analysis to obtain high precision radial velocities. This planet is the first radial velocity detection of a previously unknown circumbinary system. The planet has a mass of $0.56$ $M_{Jup}$ and orbits its host binary in 550 days with an eccentricity of 0.25. Compared to most of the previously known circumbinary planets, BEBOP-3b has a long period (relative to the binary) and a high eccentricity. There also is a candidate outer planet with a $\sim1400$ day orbital period. We test the stability of potential further candidate signals inside the orbit of BEBOP-3b, and demonstrate that there are stable orbital solutions for planets near the instability region which is where the Kepler circumbinary planets are located. We also use our data to obtain independent dynamical masses for the two stellar components of the eclipsing binary using High Resolution Cross-Correlation Spectroscopy (HRCCS), and compare those results to a more traditional approach, finding them compatible with one another.

arXiv:2507.11612v1 Announce Type: new Abstract: The detection of planets in protoplanetary disks has proven to be extremely challenging. In contrast, rings and gaps, usually attributed to planet-disk interactions, have been found in virtually every large protoplanetary (Class II) disk observed at 0.9-1.3 mm with sufficient spatial resolution (5 au). The nearby disk around MP Mus (PDS 66) stands as an exception to this rule, and its advanced age (7-10 Myr) is particularly difficult to reconcile with its apparent lack of substructures. Despite the disk's smooth appearance, Gaia data of MP Mus show a significant proper motion anomaly, signalling the presence of a companion. Here we present ALMA 3 mm observations of the system with comparable high spatial resolution to previous 1.3 mm data. The new observations pierce deeper into the disk midplane and reveal an inner cavity (<3 au) and a ring at 10 au. The disk structure inferred from ALMA observations narrows down the properties of the companion to a gas giant orbiting at 1-3 au, and hydrodynamic simulations further confirm that such a planet can produce the observed cavity. These independent pieces of evidence constitute an indirect but compelling detection of an exoplanet within a protoplanetary disk using Gaia astrometry. MP Mus is the first system in which undetected substructures are revealed thanks to the lower optical depths at longer wavelengths, suggesting that rings and gaps are even more abundant than what is currently believed.

arXiv:2507.11612v1 Announce Type: new Abstract: The detection of planets in protoplanetary disks has proven to be extremely challenging. In contrast, rings and gaps, usually attributed to planet-disk interactions, have been found in virtually every large protoplanetary (Class II) disk observed at 0.9-1.3 mm with sufficient spatial resolution (5 au). The nearby disk around MP Mus (PDS 66) stands as an exception to this rule, and its advanced age (7-10 Myr) is particularly difficult to reconcile with its apparent lack of substructures. Despite the disk's smooth appearance, Gaia data of MP Mus show a significant proper motion anomaly, signalling the presence of a companion. Here we present ALMA 3 mm observations of the system with comparable high spatial resolution to previous 1.3 mm data. The new observations pierce deeper into the disk midplane and reveal an inner cavity (<3 au) and a ring at 10 au. The disk structure inferred from ALMA observations narrows down the properties of the companion to a gas giant orbiting at 1-3 au, and hydrodynamic simulations further confirm that such a planet can produce the observed cavity. These independent pieces of evidence constitute an indirect but compelling detection of an exoplanet within a protoplanetary disk using Gaia astrometry. MP Mus is the first system in which undetected substructures are revealed thanks to the lower optical depths at longer wavelengths, suggesting that rings and gaps are even more abundant than what is currently believed.

Nature, Published online: 16 July 2025; doi:10.1038/d41586-025-02201-w

A planet that orbits closely to its young host star has been observed to induce large magnetic eruptions on the star. These flares might rapidly blow away the planet’s atmosphere, leaving behind a dense core within a few hundred million years.

Nature, Published online: 16 July 2025; doi:10.1038/s41586-025-09163-z

Observations at infrared and millimetre wavelengths of the young protostar HOPS-315 show a gaseous disk captured at the point at which solids are first starting to condense, the t = 0 for planet formation.

Nature, Published online: 16 July 2025; doi:10.1038/d41586-025-02245-y

Astronomers get rare glimpse of earliest stages of planet formation around a baby star.

Nature, Published online: 16 July 2025; doi:10.1038/d41586-025-02058-z

Observations of a young star offer a glimpse of the high-temperature conditions that shaped rock formation in the early Solar System.

X-ray: NASA/CXC/RIT/A. Varga et al.; Illustration: NASA/CXC/SAO/M. Weiss; Image Processing: NASA/CXC/SAO/N. Wolk

A star is unleashing a barrage of X-rays that is causing a closely-orbiting, young planet to wither away an astonishing rate, according to a new study using data from NASA’s Chandra X-ray Observatory and described in our latest press release. A team of researchers has determined that this planet will go from the size of Jupiter down to a small, barren world.

This graphic provides a visual representation of what astronomers think is happening around the star (known as TOI 1227) and a planet that is orbiting it at a fraction the distance between Mercury and the Sun. This “baby” planet, called TOI 1227 b, is just about 8 million years old, about a thousand times younger than our Sun. The main panel is an artist’s concept that shows the Jupiter-sized planet (lower left) around TOI 1227, which is a faint red star. Powerful X-rays from the star’s surface are tearing away the atmosphere of the planet, represented by the blue tail. The star’s X-rays may eventually completely remove the atmosphere.

The team used new Chandra data — seen in the inset — to measure the amounts of X-rays from TOI 1227 that are striking the planet. Using computer models of the effects of these X-rays, they concluded they will have a transformative effect, rapidly stripping away the planet’s atmosphere. They estimate that the planet is losing a mass equivalent to a full Earth’s atmosphere about every 200 years.

The researchers used different sets of data to estimate the age of TOI 1227 b. One method exploits measurements of how TOI 1227 b’s host star moves through space in comparison to nearby populations of stars with known ages. A second method compared the brightness and surface temperature of the star with theoretical models of evolving stars. The very young age of TOI 1227 b makes it the second youngest planet ever to be observed passing in front of its host star (a so-called transit). Previously the planet had been estimated by others to be about 11 million years old.

Of all the exoplanets astronomers have found with ages less than 50 million years, TOI 1227 b stands out for having the longest year and the host planet with the lowest mass. These properties, and the high dose of X-rays it is receiving, make it an outstanding target for future observations.

A paper describing these results has been accepted publication in The Astrophysical Journal and a preprint is available here. The authors of the paper are Attila Varga (Rochester Institute of Technology), Joel Kastner (Rochester Institute of Technology), Alexander Binks (University of Tubingen, Germany), Hans Moritz Guenther (Massachusetts Institute of Technology), and Simon J. Murphy (University of New South Wales Canberra in Australia).

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory

Learn more about the Chandra X-ray Observatory and its mission here:

https://www.nasa.gov/chandra

https://chandra.si.edu

Visual Description

This release features an artist’s illustration of a Jupiter-sized planet closely orbiting a faint red star. An inset image, showing the star in X-ray light from Chandra, is superimposed on top of the illustration at our upper left corner.

At our upper right, the red star is illustrated as a ball made of intense fire. The planet, slightly smaller than the star, is shown at our lower left. Powerful X-rays from the star are tearing away the atmosphere of the planet, causing wisps of material to flow away from the planet’s surface in the opposite direction from the star. This gives the planet a slight resemblance to a comet, complete with a tail.

X-ray data from Chandra, presented in the inset image, shows the star as a small purple orb on a black background. Astronomers used the Chandra data to measure the amount of X-rays striking the planet from the star. They estimate that the planet is losing a mass equivalent to a full Earth’s atmosphere about every 200 years, causing it to ultimately shrink from the size of Jupiter down to a small, barren world.

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Corinne Beckinger
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
corinne.m.beckinger@nasa.gov

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Details Last Updated Jul 16, 2025 EditorLee MohonContactCorinne M. Beckingercorinne.m.beckinger@nasa.gov Related Terms

• Astrophysics
• Chandra X-Ray Observatory
• Exoplanet Science
• Exoplanets
• Marshall Astrophysics
• Marshall Space Flight Center
• Science & Research
• Studying Exoplanets
• The Universe

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arXiv:2507.11225v1 Announce Type: new Abstract: The variation in hot Jupiter (HJ) occurrence across stellar environments holds clues as to the dominant formation channels of these extreme planets. Recent studies suggest HJ hosts preferentially reside in regions of high phase space density, possibly reflecting natal environmental conditions. These regions are kinematically cold (|v| < 40 km/s), prompting the alternative hypothesis that the correlation reflects an age bias: planetary systems in overdensities are systematically younger and therefore less likely to have undergone tidal inspiral and destruction. We test whether the apparent excess of HJs in phase space overdensities arises from differences in intrinsic host properties -- mass, metallicity, age -- which may correlate with phase space density or whether there is evidence for an additional environmental effect. We derive homogeneous estimates for the mass, metallicity, and age of planet-hosting stars using 2MASS and Gaia DR3 photometry, parallaxes, and self-consistent spectroscopic and spectrophotometric observables. In a sample of 2265 confirmed exoplanet hosts, we find a significant relative excess of HJs orbiting stars in overdense regions. However, we also find that overdensities preferentially host younger, more massive, and more metal-rich stars compared to underdensities. After correcting for these differences, either by detrending the phase space density against age or by matching host properties across subsamples, we find no significant differences in the HJ populations between over- and underdense regions. Our results suggest that the previously reported correlation between HJ occurrence and phase space density is driven by underlying differences in host star demographics rather than an intrinsic environmental effect.

arXiv:2507.11225v1 Announce Type: new Abstract: The variation in hot Jupiter (HJ) occurrence across stellar environments holds clues as to the dominant formation channels of these extreme planets. Recent studies suggest HJ hosts preferentially reside in regions of high phase space density, possibly reflecting natal environmental conditions. These regions are kinematically cold (|v| < 40 km/s), prompting the alternative hypothesis that the correlation reflects an age bias: planetary systems in overdensities are systematically younger and therefore less likely to have undergone tidal inspiral and destruction. We test whether the apparent excess of HJs in phase space overdensities arises from differences in intrinsic host properties -- mass, metallicity, age -- which may correlate with phase space density or whether there is evidence for an additional environmental effect. We derive homogeneous estimates for the mass, metallicity, and age of planet-hosting stars using 2MASS and Gaia DR3 photometry, parallaxes, and self-consistent spectroscopic and spectrophotometric observables. In a sample of 2265 confirmed exoplanet hosts, we find a significant relative excess of HJs orbiting stars in overdense regions. However, we also find that overdensities preferentially host younger, more massive, and more metal-rich stars compared to underdensities. After correcting for these differences, either by detrending the phase space density against age or by matching host properties across subsamples, we find no significant differences in the HJ populations between over- and underdense regions. Our results suggest that the previously reported correlation between HJ occurrence and phase space density is driven by underlying differences in host star demographics rather than an intrinsic environmental effect.