astro-ph.EP Archives

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

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 […]

Left: Radiative cooling rates for TOI-238 b: the H-He atmosphere with solar metallicity (top panel) and the atmosphere enriched in metals 200 times over solar metallicity (bottom panel). The plot format matches that of Fig. 2. Center: Volume heating rates for TOI-238 b: the H-He atmosphere with solar metallicity (top panel) and the atmosphere enriched in metals 200 times over solar metallicity (bottom panel). The plot format matches that of Fig. 3. Right: Population of hydrogen species and heavy (metal) ions: the H-He atmosphere with solar metallicity (top panel) and the atmosphere enriched in metals 200 times over solar metallicity (bottom panel). The plot format matches that of Fig. 4. -- astro-ph.EP

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

Escape Of Water- And Metal-enriched Atmospheres From Compact Hot mini-Neptunes With CHAIN

by Keith CowingJune 3, 2026June 3, 2026

Recent observations reveal that atmospheric compositions of close-in sub-Neptunes are diverse and can differ strongly from pure H/He-dominated.

Abundances (w.r.t. H nuclei) of main C and O carriers in the baseline and full chemistry models without transport. C species represent the combination of all species containing carbon, but not oxygen; O species represent the species containing oxygen, but not carbon; C+O species represent the species containing both carbon and oxygen. From all the grouped species, the initially present H2O, CO2 , CO and CH4 are excluded. Solid lines represent ice-phase species, and dashed lines represent gas-phase species. -- astro-ph.EP

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

Metamorphoses Of Carbon And Oxygen In Protoplanetary Discs: How Chemistry And Radial Drift Transform Inner Disc C/O Ratios

by Keith CowingJune 2, 2026June 2, 2026

The chemical composition of a protoplanetary disc is sensitive to its thermal structure and dust properties, and can provide insights into the disc evolution.

The planetary direct-extracted spectrum extraction steps. Top left: The original stellar spectral matrix. The red dashed lines indicate T1 and T4, while the white dashed lines mark T2 and T3. Bottom left: The master stellar spectrum, derived by averaging all spectra within the eclipse phase (T23). Top right: The planetary residual flux matrix, obtained by dividing the original flux matrix by the master stellar spectrum. Bottom right: The final WASP-18b direct-extracted spectrum (black) and the Gaussian filtered spectrum (light blue). -- astro-ph.EP

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

Detection Of CO, H2O, And OH In WASP-18b With JWST/NIRISS Using Direct-Extracted Spectra And Cross-Correlation

by Keith CowingJune 2, 2026June 2, 2026

The James Webb Space Telescope (JWST) has revolutionized the characterization of exoplanetary atmospheres, offering unprecedented sensitivity to probe their chemical and physical properties.

Final best fit for VHS 1256 b. Top panel: same as Fig. 8, but using the two-column approach. Best fit parameters are Teff = 1153 K, log g = 4.0 dex, [M/H] = 0.08 dex, C/O = 0.60, R = 1.2 RJup, with an α = 0.62 so a linear combination of fsed = 0.7 (62%) in grey dashed and fsed = 2.4 (38%) in grey solid line. Both grey fsed components have been scaled by their proportion and multiplied by a factor of 0.6 for visibility. The two fsed component spectra are shown with reduced resolution for visibility. Bottom panel: same as Fig. 8. -- astro-ph.EP

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

Next-generation Exo-REM Atmospheric Models: Application To VHS 1256 b To Emulate Patchy Clouds

by Keith CowingJune 2, 2026June 2, 2026

Condensate clouds are a defining feature of brown dwarf and exoplanet atmospheres, producing a broad range of colours on the CMD and giving rise to spectral features such as the […]

Integrated intensity maps of the dust continuum

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

The Asymmetric Carbon-rich Chemistry 0f The planet-forming Disk 0f HD 142527 Triggered By Late Infall

by Keith CowingJune 1, 2026June 1, 2026

The planet-forming disk of HD 142527 is known for its azimuthally asymmetric dust trap, shadows, and spiral arms.

Evolutions of fiducial planetesimals with different chondritic compositions. Each plot is the contour of one quantity across time and radial location. Note that the total radius decreases due to sintering. From top row to bottom: EH, OC, CV, and CI bodies. Physical quantities from left to right: (i) temperature, (ii) condensed + gaseous C abundance normalized to the initial reservoir; > 1 relative abundance occurs due to sintering concentrating C, (iii) porosity and (iv) gas pressure; hatched areas are completely sintered with no meaningful gas pressure. -- astro-ph.EP

Astrochemistry, Astrogeology, Meteorites & Asteroids, Status Report

Modeling Carbon Outgassing From Chondritic Planetesimals

by Keith CowingJune 1, 2026June 1, 2026

The thermochemical evolution of planetesimals is an underprobed stage of volatile delivery to terrestrial planets during their formation, and may contribute to the volatile depletion of the Earth relative to […]

Completeness of our GaiaPMEX search for binaries. Each panel represents one of the GaiaPMEX references. The shaded area shows the completeness of the combined RUWE+PMa signal, with the dotted blue line and the dashed red line indicating the 50% contour level given by RUWE and PMa alone, respectively. Overplotted are SHINE detections, each assigned to the closest reference star to its target. Squares indicate stars with no RUWE and PMa measurements; triangles represent stars without PMa; dots indicate stars with both RUWE and PMa. The companions are colored according to their detection method: red (DI), gold (RV), green (GaiaNSS), black (GaiaPMEX); those also detected by GaiaPMEX have a black edge. Finally, violet markers indicate companions, only detected by GaiaPMEX, with a minimum mass in the substellar regime. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

The SPHERE Infrared Survey For Exoplanets (SHINE) V. Full Sample Characterization

by Keith CowingMay 29, 2026May 29, 2026

Surveys of large stellar samples are the prime means through which the prevalence of exoplanets can be derived, and crucial constraints to planet formation models can be set.

Each panel shows the T(P) profiles for the clear atmosphere (red line) and cloudy atmosphere (blue line) computed for a sub-Neptune belonging to our sample of 8 sub-Neptunes. The phases of the interfaces for TOI-270 d and TOI-1231 b are shown in Figure 5, while those for the rest of the sub-Neptunes in our sample are shown here. Similar to Figure 5, the thicker lines depict the convective regions of the atmosphere. The locus of blue and red crosses show the P and T locations of the atmosphere-mantle interface computed by coupling our atmosphere model with the interior structure model for the cloudy and clear models, respectively. The P − T location and the T(P) profiles are overlaid on the phase–diagram for silicates, depicting its solid and molten phases as blue and red shaded regions. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Impact of Clouds on the Atmosphere-Mantle Interface of Sub-Neptunes

by Keith CowingMay 29, 2026May 29, 2026

Sub-Neptunes are among the most common type of close-in planets found in our galaxy, yet their bulk composition remains largely uncertain; H-rich envelopes overlaying rocky cores, volatile-rich planets, and carbon-rich […]

Examples of materials with extremely high porosities (ϕ > 80%). a) Heesch & Laves (1933) 94.45% rigid packing structure. b) and c) pictures from Blum & Schr¨apler (2004) experiments of SiO2 agglomerates with 85% porosity. d) Water ice aggregates with 89% porosity observed with a long-distance microscope (Gundlach et al. 2011). Bottom Row: experimental pictures from the Core-Mantle Particle Sedimentation System e) Cryogenically cooled chamber with 15 mm high needles that serve as sample mounts for ice aggregates. f) Micrometer-sized water ice spheres as seen from the scanning electron microscope. g) Fractal ice aggregates as seen from the long distance microscope. Each individual grain has been highlighted in yellow on the right side of the picture. -- astro-ph.EP

Astrochemistry, Astrogeology, Icy Worlds, Imaging & Spectroscopy, Status Report

The Physical Nature of Regolith on Icy Moons

by Keith CowingMay 28, 2026May 28, 2026

Estimating surface properties such as porosity and grain sizes is key for planning lander missions and landing site selection on icy moons.

astro-ph.EP

Jets and Superrotation in Deep and Shallow Planetary Atmospheres

Escape Of Water- And Metal-enriched Atmospheres From Compact Hot mini-Neptunes With CHAIN

Metamorphoses Of Carbon And Oxygen In Protoplanetary Discs: How Chemistry And Radial Drift Transform Inner Disc C/O Ratios

Detection Of CO, H2O, And OH In WASP-18b With JWST/NIRISS Using Direct-Extracted Spectra And Cross-Correlation

Next-generation Exo-REM Atmospheric Models: Application To VHS 1256 b To Emulate Patchy Clouds

The Asymmetric Carbon-rich Chemistry 0f The planet-forming Disk 0f HD 142527 Triggered By Late Infall

Modeling Carbon Outgassing From Chondritic Planetesimals

The SPHERE Infrared Survey For Exoplanets (SHINE) V. Full Sample Characterization

Impact of Clouds on the Atmosphere-Mantle Interface of Sub-Neptunes

The Physical Nature of Regolith on Icy Moons

Direct Dating Of 3.5 Ga Biogenic Carbon In A Microbial Mat Remnant, Singhbhum Craton, India

The VLA and High-Frequency SETI: Expanding The Search for Life

GEMS JWST: HATS(-6 b): A Sub-solar Metallicity Giant Planet With Water, Methane And Ammonia In Its Atmosphere

The Tidal Venus Phenomenon: Demographics and Case Studies

RNA Droplets May Have Helped Start life on Earth