astro-ph.EP] Archives - Astrobiology

Atmosphere loss of Barnard’s Star planets, under various assumptions of planet masses, bulk densities, and initial atmospheric mass fraction. The mass range tested for a given planet is between its minimum mass (based on RV data; B25) and 2.5 times the minimum mass (see Section 2). The bulk densities 𝜌, used to calculate planet radius in the evolution models, span a liberal range: the Solar System rocky planets have densities between 3.93 g cm−3 (Mars) and 5.51 g cm−3 (Earth). No matter what assumptions are made, the planets are completely stripped of their atmospheres within 2 Gyr. The atmospheres survive longer if the planets are more massive, denser, farther from the star, and begin with a larger atmospheric mass fraction. — astro-ph.EP

The Barnard’s Star Planetary System: Stability, Composition, and Evolution of Four Sub-Earth Exoplanets

by Keith CowingJune 24, 2026June 24, 2026

Barnard’s Star is the nearest single star to the Sun (1.8 pc), and hosts four recently-discovered planets.

Simulated emission spectra of GJ 3929 b for various surface (left) and atmospheric (right) compositions compared to the measured eclipse depths from our FN-PCA calculation,

AI - 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

by Keith CowingJune 8, 2026June 26, 2026

Despite their large abundance, it is still unknown whether and under what conditions rocky planets around M dwarf stars can host atmospheres.

Graphical Abstract -- Titan's Resources and their Utilization

Icy Worlds, Imaging & Spectroscopy, Life Support Systems, Missions & Hardware, Nanotechnology & SynBio, Status Report, Titan

Titan’s Resources and their Utilization

by Keith CowingJune 8, 2026June 8, 2026

Saturn’s moon Titan is a unique environment in the solar system. It is the only moon with an atmosphere, composed primarily of the gases N2 and CH4. It is also […]

Moment-zero maps for all of the Lupus and Upper Sco sources. The grayscale panels represent non-detections. No H2CO data was available for Upper Sco 6 and for the p-4-3 line for Lupus 6, Upper Sco 9, and Upper Sco 10. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): Formaldehyde (H2CO) Emission And Its Links To Disk Properties

by Keith CowingJune 7, 2026June 7, 2026

Protoplanetary disks are rotating structures of gas and dust surrounding young stars, serving as the birth places of planets. Understanding the chemical evolution of organic materials in these disks is […]

Initial structure of the Impact Plume 60 s post impact. The impactor strikes from the left, at a 60° angle from horizontal, with the sun located to the right.There is a visible asymmetry in the plume due to the direction of impact; the “hole” on the right side of the plume is a bubble in this 2D slice of a fully 3D plume due to the removal of water vapor-rock mixtures from the simulation during the sampling from SOVA into DSMC codes (Prem et al. 2015). (Top) the plume contains a region of high density (~1022 molecules/m3 ) just above the point of impact, which rapidly drops toward the edges of the plume. (Bottom, left) The high plume densities correspond to short mean free paths for the vapor molecules. (Bottom, right) Comparing this mean free path with the length scale of the density gradient reveals very small Knudsen numbers throughout; the entire plume (except for the very outermost edges) is clearly within the continuum flow regime at this time, rather than the slip-flow, Knudsen, or Free Molecular regimes. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Comets and Asteroids, Cryobiology, Icy Worlds, Imaging & Spectroscopy, Impact events, Mapping, Geodesy, Cartography, Bathymetry, Mercury, Status Report

Transport of Water In A Transient, Impact-Generated Atmosphere On Mercury

by Keith CowingJune 5, 2026June 26, 2026

Mercury’s polar cold traps host water ice deposits that are likely populated with impact-delivered water via Mercury’s exosphere.

Upper: Transit depths of V1298 Tau e as a function of wavelength, reduced with Eureka!. The blue and red curves show the best-fit transmission spectra from our free re- trieval with and without CS2, respectively. Including CS2 yields a decisive improvement in the Bayesian evidence (∆ ln Z = 33.2), corresponding to an 8.4σpreference. Lower: Absorption cross sections of the nine dominant molecular species included in our free retrieval and forward model. While a wider range of additional species were explored using POSEIDON opacity database, CS2 uniquely reproduces both the∼4.6–4.7 µm feature and the sharpened peak near ∼4.3 µm that cannot be explained by CO2 or CO alone. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Photochemical CS2 Gas Detected On A 20-Myr-old Exoplanet

by Keith CowingJune 3, 2026June 3, 2026

Probing the atmospheres of young exoplanets offers a powerful window into how planetary systems evolve and the physical and chemical processes that drive those early evolutions.

(left) An illustration of Ames MGCM in c48 (1.875°) cubed-sphere grid over martian topography. Tile boundaries are drawn in red. (from Ames MGCM User Guide); (right) Three stretched grids that illustrate the effect of stretch factor (S) on stretching a C16 cubed-sphere. (From Bindle et al., 2021) -- astro-ph.EP

AI - Data - Apps - Cybernetics, Astrogeology, Atmospheres, Climate, Weather, Desert Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Status Report

Towards a Foundation Model for the Martian Atmosphere

by Keith CowingJune 1, 2026June 26, 2026

The martian atmosphere hosts dynamical phenomena ranging from planet-encircling dust storms to mesoscale orographic clouds and nocturnal low-level jets.

Pole-on views of the orbital positions of Proxima d (small black dot) and b (large black dot) during each enhanced-emission event. The telescope symbol and vertical dotted line indicate the time of inferior conjunction and the observer’s direction. Orbital motion is clockwise. Each configuration is labeled by its BJD. Proxima Centauri is represented by the central orange dot. -- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Proxima Centauri, Radiation, Space Weather & Heliophysics, Status Report

Star-planet Interaction In The Proxima System

by Keith CowingMay 26, 2026May 26, 2026

(Abridged) We search for evidence of star-planet magnetic interactions in the nearby Proxima Centauri planetary system using high-quality, high-spectral-resolution optical observations.

Schematic cross sections of Earth and Mars, showing the major internal components and atmospheric components, to scale. For simplicity, oceanic and continental crust for Earth are not distinguished, nor is the interior structure of Earth’s mantle shown. -- astro-ph.EP

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Desert Worlds, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mars, Origin & Evolution of Life, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Mars As An Exoplanet: Lessons From A Planet At The Edge Of Habitability

by Keith CowingMay 20, 2026May 20, 2026

Mars is the Solar System’s canonical small, rocky planet that transitioned from early geologic activity and surface liquid water to a cold and arid planet with a thin, cold, CO2-dominated […]

Kernel density estimates of the bulk elemental mass fractions of the initial planet population. The population is separated into planets that formed inside and outside the water ice line. Planets formed outside the ice line exhibit systematically higher oxygen and hydrogen mass fractions, reflecting enhanced accretion of volatile-rich material, which in turn leads to a relative depletion of refractory elements such as magnesium, iron, sulfur, and silicon. High bulk nitrogen and carbon abundances are exclusively associated with planets that formed outside the ice line. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

The Role of Formation Location in Shaping Sulfur-, Nitrogen-, and Carbon-Bearing Species in Super-Earth and Sub-Neptune Atmospheres

by Keith CowingMay 17, 2026May 17, 2026

Atmospheric compositions of sub-Neptunes and super-Earths are often interpreted as tracers of formation location relative to volatile ice lines.