![Wavelength distributions of candidate spectral lines retained at each step of the line-selection procedure. The histograms show the initial linelist (light), lines retained after automated vetting (intermediate), and the final manually vetted sample (dark). The shaded background regions indicate approximate wavelength ranges for the Y, J, H, and K-bands.-- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Elemental.png?resize=1200%2C716&ssl=1)
[astro-ph.SR] Stellar elemental abundances provide important constraints on the chemical environments from which planets form. M and late-K dwarfs are prime targets for the characterization of small exoplanets, yet their […]
K2-18
![Log–log relation between age and rotation period for M dwarfs. Black squares show the Engle & Guinan (2023) sample. Filled circles are cluster members from Curtis et al. (2020) and Godoy-Rivera et al. (2021), colour-coded by spectral type (M2–M6). The solid blue curve is the median fit. Dark- and light-grey bands denote the 68% and 95% posterior predictive regions, including intrinsic astrophysical scatter. Triangles with error bars indicate the target stars analysed in this work. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Stellar.png?resize=1200%2C720&ssl=1)
Posted inStellar Cartography
Stellar Ages of M Dwarf Hosts of Temperate Sub-Neptunes
[astro-ph.EP] Measuring M dwarf ages is a central challenge in stellar astrophysics. These stars evolve so slowly that isochrone fitting gives little constraint, requiring alternative methods based on rotation, activity, […]
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Stellar Cartography, Water/Hycean Worlds & Oceanography
Characterising M Dwarf Host Stars Of Two Candidate Hycean Worlds
Planetary systems orbiting M dwarf host stars are promising targets for atmospheric characterisation of low-mass exoplanets.
Posted inBiophysics, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Proxima Centauri, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography
The Time Evolution Of The Ultraviolet Habitable Zone
For stars hosting Circumstellar Habitable Zone (CHZ) exoplanets, we investigate the time-evolution of their ultraviolet habitable zone (UHZ), the annular region around a star where an exoplanet could experience a […]
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography
Planets Contain More Water Than Previously Thought
Most of a planet’s water is generally not found on the surface, but is hidden deep inside. This affects the potential habitability of distant worlds, as model calculations by researchers […]
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography
The Hycean Paradigm in the Search for Life Elsewhere
The search for habitable conditions and signs of life on exoplanets is a major frontier in modern astronomy. Detecting atmospheric signatures of Earth-like exoplanets is challenging due to their small […]
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Biogenic Sulfur Gases As Biosignatures On Temperate Sub-Neptune Waterworlds
Theoretical predictions and observational data indicate a class of sub-Neptune exoplanets may have water-rich interiors covered by hydrogen-dominated atmospheres. Provided suitable climate conditions, such planets could host surface liquid oceans.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
Secular Orbital Dynamics of the Possibly Habitable Planet K2-18 b with and without the Proposed Inner Companion
The transiting planet K2-18 b is one of the best candidates for a relatively nearby world harboring biological life. The long-term orbital evolution of this planet is investigated using theoretical […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release
Webb Discovers Methane, Carbon Dioxide in Atmosphere of K2-18 b
A new investigation with NASA’s James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and […]