atmosphere Archives

Planets orbiting M-type stars (Teff < 4000K) are plotted in black on the orbital period–planet radius diagram. TOI-1883 b is highlighted in red.

The Mass of TOI-1883 b: A Low Density Super-Neptune In The Ridge Regime Transiting An Early-M dwarf

by Keith CowingJune 8, 2026June 8, 2026

Recent large-scale transit surveys conducted by space telescopes such as Kepler and TESS have revealed a vast number of exoplanets, uncovering the diversity of their population.

Comparison of input SEDs used in this study and molecular photoabsorption cross sections relevant to Archean-analog photochemistry. The horizontal bars indicate the FUV and NUV wavelength intervals used to compute the stellar FUV/NUV ratios in Figures 5 and 7. Top: Top-of-atmosphere (ToA) stellar energy fluxes at TRAPPIST-1 e from 120–350 nm for five SEDs: Peacock+2019 (P19) Median (orange) (S. Peacock et al. 2019), Mega-MUSCLES (W21) Adaptive (yellow), Mega-MUSCLES (W21) SEM (light blue) (D. J. Wilson et al. 2021), a “Revised PHOENIX” model (dark blue) constrained by the HST observations published in D. J. Wilson et al. (2021), and a scaled modern Sun (red) (G. Thuillier et al. 2004). All SEDs are scaled to TRAPPIST-1 e’s ToA irradiance. Bottom: Representative molecular cross sections for CH4 (pink), CO2 (black), H2O (green), O2 (light blue), and O3 (dark blue) are shown, highlighting the wavelength overlap between the cross sections and the stellar UV output. Where both the flux and the cross section are large, photolysis rates increase and influence production and loss pathways throughout the atmosphere. -- astro-ph.EP

Astronomy & 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

by Keith CowingJune 7, 2026June 7, 2026

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, […]

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.

Synthetic Aperture Radar (SAR) images of Ligeia Mare and Ontario Lacus obtained by the Cassini Spacecraft (NASA/JPL-Caltech/ASU/Cornell) and corresponding lake bathymetry. (a) Ontario Lacus: SAR image collected on 12 Jan. 2010 centered at 72°S 183°W. Image ID: PIA13172. Red circled region indicates potential smooth wave-modified coast (Palermo et al., 2024; Wall et al., 2010); (b) Ligeia Mare: a mosaic of SAR images collected between February 2006 and April 2007 and combined to create image PIA17031 centered at 79°N 248°W. Locations of a potential straight wave-modified coast (Wall et al., 2010) and the location of the magic island observations (Hofgartner et al., 2014, 2016) are annotated; SAR-based bathymetric maps of (c) Ontario Lacus and (d) Ligeia Mare (Hayes, 2016) were used as inputs to our wave model. -- Journal of Geophysical Research: Planets

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Cryobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Titan, Water/Hycean Worlds & Oceanography

Modeling the Seasonality of Wind-Driven Hydrocarbon Waves in Titan’s Polar Lakes

by Keith CowingJune 5, 2026June 5, 2026

Titan, the only body in the solar system aside from Earth with standing liquids on its surface, has high-latitude hydrocarbon lakes and seas. As Titan’s atmosphere generates light winds, there […]

Artist’s impression of Plato, the European Space Agency’s mission to discover Earth-like planets orbiting sun-like stars. The research detailed in this article hopes to help missions, like Plato, narrow this search. -- ESA

Astrochemistry, Astrogeology, Astropharmacy / Biotechnology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release

New Model Refines Search For Habitable Planets

by Keith CowingJune 5, 2026June 5, 2026

Researchers have developed the Smaller Than Earth Habitability Model (STEHM) to assess which planets can maintain life-supporting atmospheres, focusing on size and atmospheric dynamics.

The heatmap shows the practical recovery threshold for the stellar–planetary metallicity correlation: small and moderate surveys lose sensitivity once intrinsic scatter becomes large, whereas Ariel-scale samples maintain high recovery fractions across the tested scatter range. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

HERMES: HiERarchical Modelling for Exoplanet Science

by Keith CowingJune 5, 2026June 5, 2026

ESA’s Ariel Space Mission will characterise the atmospheres of approximately 1000 exoplanets to quantify population-level trends.

From Lothringer et al. (2022). The HST/WFC3-UVIS/G280 transmission spectrum of WASP-178b shows enormous absorption in the NUV by metal species. Observations of other planets hint at a trend of NUV metal absorption increasing somewhere between equilibrium temperatures of 1900 and 2200 K. -- astro-ph.IM

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Characterizing Transiting Exoplanet Atmospheres in the 2030s with the Hubble Space Telescope

by Keith CowingJune 5, 2026June 5, 2026

The Hubble Space Telescope inaugurated the era of exoplanet atmospheric characterization. While the James Webb Space Telescope has largely taken up the mantle of infrared atmospheric characterization, Hubble’s unique short-wavelength […]

The simulated occurrence rates of planets in both simulated (blue) and known (orange) planetary systems around nearby stars. Top left: All planet periods. Top right: All planet radii. Bottom left: Small planet (R < 6 R⊕) periods. Bottom right: Giant planet (R > 6 R⊕) periods. Additional predicted planets in the systems with known planets are not shown. astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

Predictive Rankings of the Probability for Temperate Terrestrial Worlds for the HWO ExEP Mission Star List

by Keith CowingJune 4, 2026June 4, 2026

The Habitable Worlds Observatory (HWO) is NASA’s flagship mission design from the Decadal Survey on Astronomy and Astrophysics 2020, meant to observe temperate terrestrial planets via direct imaging and use […]

A series of numerical integrations using an idealized GCM (Isca, Vallis et al. 2018) configured by G. Colyer in an Earth-like setting but with the rotation rate varying from that for Earth (𝛺𝐸) to 𝛺𝐸/100. The upper row shows zonally averaged zonal velocity (colors) and temperature (contours) and the lower panel shows a normalized excess angular momentum (colors), which is a useful measure of superrotation, and meridional overturning streamfunction (contours). The horizontal axis is latitude, from −90 to +90. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report

Jets and Superrotation in Deep and Shallow Planetary Atmospheres

by Keith CowingJune 4, 2026June 4, 2026

Zonal flows in planetary atmospheres are ubiquitous, and nearly all the planets in the Solar System have flows that are zonally rather than meridionally aligned. Jets, which are essentially concentrated […]

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.

atmosphere

The Mass of TOI-1883 b: A Low Density Super-Neptune In The Ridge Regime Transiting An Early-M dwarf

Ultraviolet-Driven Atmospheric Degeneracies Challenge Conventional Biosignature Frameworks for Terrestrial Planets with Ultracool M Dwarf Hosts: An Archean-Analog TRAPPIST-1 e Case Study

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

Modeling the Seasonality of Wind-Driven Hydrocarbon Waves in Titan’s Polar Lakes

New Model Refines Search For Habitable Planets

HERMES: HiERarchical Modelling for Exoplanet Science

Characterizing Transiting Exoplanet Atmospheres in the 2030s with the Hubble Space Telescope

Predictive Rankings of the Probability for Temperate Terrestrial Worlds for the HWO ExEP Mission Star List

Jets and Superrotation in Deep and Shallow Planetary Atmospheres

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

Astrobiologist Dale Andersen’s Antarctic Field Report: 9 November 2026: Lake Untersee Basecamp Update

Astrochemistry: Hubble and JWST Observe Star Formation in The Carina Nebula

Mapping the Historical Roots of Astrobiology: A Reference Publication Year Spectroscopy (RPYS) Analysis

The Agentic Observer Hackathon: Autonomous Decision-making in Simulated Astronomical Surveys

Tracking The Evolution of sub-Neptunes. I. Gyrochronology of Planet Hosting Stars