![Post-processed NIRCam images for the two epochs, with 1- and 2-σ contours of the expected position, computed with the posteriors of the Octofitter results: in white without including the images in the fit, and in green including the images, but without making a connection between flux and atmospheric model. The postprocessing method is described in Sec. 2.3. When including the images, some walkers tend towards the feature whose location coincides with the expected position of planet b. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/An-Updated.png?resize=1200%2C719&ssl=1)
[astro-ph.EP] Epsilon Eridani b, the nearest known Jupiter analog, has its orbit and mass constrained from radial velocity (RV) and absolute astrometry, and its atmosphere from JWST/NIRCam imaging upper limits […]
metallicity
Posted inAstrogeology
Planet Formation at Cosmic Dawn: Planetesimals in H2O-rich Disks around Low-mass Stars
[The Astrophysical Journal Letters]. Primordial, or Population III (Pop III), supernovae (SNe) were the first nucleosynthetic engines in the Universe, forging the heavy elements required for the later formation of […]
![The best-fit chemical equilibrium models to our co-added data performed with three different retrieval suites. For all chemical equilibrium fits, the models produced poor fits to several features on the spectrum, namely near 3 µm and between 4 − 5 µm region. For the 4.3 micron region, the differences between features are due to a combination of differences in the retrieval framework (namely prior constraints) and chemical networks used (FastChem vs GGChem) for each retrieval suite. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/GEMS-JWST.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
GEMS JWST: HATS(-6 b): A Sub-solar Metallicity Giant Planet With Water, Methane And Ammonia In Its Atmosphere
[astro-ph.EP] HATS-6 b is one of several recently discovered Giant Exoplanets orbiting M-dwarf Stars (GEMS) and is part of a JWST survey that aims to compare bulk and atmospheric properties […]
![Top left: (pgas, Tgas) cross-section through the terminators of WASP-69 b, with the location of the CH4 quench point overlaid (light blue line). We define the CH4 quench level as the pressure where the absolute relative difference between the equilibrium and disequilibrium concentrations first exceeds 10−3. Top right: Column densities in the line-of-sight direction in the atmosphere of WASP-69 b for [M/H] = 1.0, and C/O = 0.55 for CH44. Bottom: The same as for CH4 but now for SO2 (left) and CO2 (right). The terminator pressure scale is used as a radius axis. The hotspot offset at 10−4 bars is reflected in the column density of SO2, with larger concentrations being formed on the evening terminator. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Chemical-Tracers.png?resize=1200%2C716&ssl=1)
Posted inExoplanets, -moons, -comets
Chemical Tracers For 3D Atmospheric Asymmetries On WASP-69 b
[astro-ph.EP] Warm giant exoplanets exhibit strong three-dimensional temperature contrasts that can significantly alter atmospheric chemistry through quenching and photochemistry, yet transmission spectra are commonly interpreted using one-dimensional, limb-averaged models. Such […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
HERMES: HiERarchical Modelling for Exoplanet Science
ESA’s Ariel Space Mission will characterise the atmospheres of approximately 1000 exoplanets to quantify population-level trends.
Posted inAstrochemistry, Habitable Zones, Status Report
The Habitability Trade-off: Chemical Decoupling And Quenching In Massive Galaxies
Massive galaxies experience complex evolutionary processes, including mergers and gas accretion, which can disrupt the chemical equilibrium between their stellar and gaseous components.
![Stellar [α/Fe] versus [Fe/H] for planet-hosting stars analyzed in this work (orange circles). The heat map represents the density of stars from APOGEE DR17 in the [α/M] vs [Fe/H] parameter space for reference. The black line approximately divides the thin and thick disk populations (below and above the line, respectively) as defined by D. H. Weinberg et al. 2019. The red points represent stars from the SPOCS sample from J. M. Brewer et al. (2016). The Sun is over-plotted for reference. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/05/A-Uniform-Determination.png?resize=1200%2C715&ssl=1)
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography
A Uniform Determination Of The Bulk Metallicities And Alpha Enrichments Of Confirmed Exoplanet Systems With TRES
We present a uniform spectroscopic characterization of 625 F, G, and K stars hosting 859 confirmed exoplanets using high-resolution archival optical spectra from the Tillinghast Reflector Echelle Spectrograph (TRES).
Posted inAriel Mission, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Missions & Hardware, Status Report, Stellar Cartography
Ariel Stellar Characterisation IV. Fundamental Parameters Of 18 Hot Stars In The Ariel Mission Candidate Sample
The characterisation of exoplanetary systems depends on the accurate determination of host star parameters.
Posted inAstronomy & Telescopes, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography
Characterizing Six Seismic Solar Analogs Observed By Kepler, K2, And HERMES
Solar analogs, stars that closely match the fundamental properties of the Sun, provide key benchmarks for testing stellar structure and evolution across different ages and activity levels.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Space Weather & Heliophysics
A Theoretical Study of the Structure and Elemental Abundances of HD 20794
HD-20794 is a nearby, bright, metal-poor G-type dwarf hosting a compact planetary system, including a super-Earth near the habitable zone.