![Panel (a): HR diagram of the OC members with detections. The blue solid line is the fitting results of MS. green dashed lines represent the upper and lower bounds of the MS fitted with a ±0.5 offset, and the red dashed line is the same sequence shifted upwards by 2. The color bars represent the stellar ages. Panel (b): HR diagram of the field stars with detections. Panel (c): The Galactic distribution of the selected sources from the detected OC members. Panel (d): The Galactic distribution of the selected sources from the detected field stars. -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Evolution-of.png?resize=1200%2C720&ssl=1)
[astro-ph.SR] Stellar X-ray emission serves as a direct diagnostic of coronal activity, which is fundamentally linked to coronal heating processes. It also strongly influences the atmospheres and long-term habitability of […]
M-dwarf
![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 […]
![The Rapid ASKAP Continuum Survey (RACS) radio images of radio sources associated with candidates A (J1245-2652, top row) and B (J0356-4031, bottom row) are shown at three frequencies: 887.5 MHz (left), 1367.5 MHz (centre), and 1655.5 MHz (right), with each panel covering a field of view of 65" × 65" . White ellipses show the PyBDSF source fits from the RACS catalogues, with thick solid lines indicating the fits at the frequency of the image, while thin dashed lines show fits from the other radio frequencies for comparison. Large blue crosses (×) mark radio source positions for the corresponding frequency, and small blue plus signs (+) indicate positions at other frequencies. The red stars represent the Gaia positions propagated to the corresponding RACS observation epochs using the measured proper motions. -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Archival-Diagnostics.png?resize=1200%2C720&ssl=1)
Posted inSETI & Technosignatures
Archival Diagnostics for Potential Background Contaminants Of Project Hephaistos Dyson Sphere Candidates
[astro-ph.SR] We report on the diagnostic inspection of nine Project Hephaistos Dyson Sphere candidate M-dwarfs based on archival data. By comparing the Gaia positions, propagated to the AllWISE epoch, with […]
Posted inUncategorized
An Agnostic Machine Learning Model of Photosynthetic Habitability
The search for exoplanet biosignatures is guided by whether planetary environments can sustain photosynthesis.
Posted inAstrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography
Revisiting The Exo-Mercury Candidate GJ 367 b With ESPRESSO And A Self-Consistent Tidal Distortion Model
We report revised mass and radius measurements for GJ 367 b, an ultra-short-period (7.7 hr) sub-Earth in a multi-planet system orbiting a nearby (~9 pc) M dwarf host. Previous mass […]
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes
Temperate sub-Neptune and terrestrial exoplanets could contain large inventories of water in various phases, such as water-dominated atmospheres or even oceans. Observations have shown that many exoplanets, including water worlds, […]
Posted inAI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Mapping, Geodesy, Cartography, Bathymetry, Status Report
GJ 3929 b as the First Complete Rocky Worlds DDT Data Set
Despite their large abundance, it is still unknown whether and under what conditions rocky planets around M dwarf stars can host atmospheres.
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1
Ultraviolet-Driven Atmospheric Degeneracies Challenge Conventional Biosignature Frameworks for Terrestrial Planets with Ultracool M Dwarf Hosts: An Archean-Analog TRAPPIST-1 e Case Study
The ultraviolet (UV) spectrum of a host star strongly shapes the atmospheric composition and potential biosignatures of its planets. This relationship may be especially important for the planets orbiting TRAPPIST-1, […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Press Release, Stellar Cartography
Red Dwarf Stars Detected ‘Eating’ Earth-like Planets
Astronomers have found some of the strongest evidence yet that stars can swallow their own planets.
Posted inAstronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
The First Remotely Detected Biosignature May Not Be the Most Common: Implications for JWST and HWO
The first detected member of a new astronomical class is often not representative of the underlying population, but instead reflects the selection effects of the observing technique that found it.