JWST Archives

The retrieved transmission spectrum using the results from the free retrieval plotted as a black line, along with the transmission data from NIRCam F322W2, F444W, and MIRI LRS plotted as black dots with 1 sigma error bars. Contributing absorption is plotted in various colors to show where gas species contribute the transmission spectrum. From the gas contributions we can see by eye that the absorption of CS2 matches the features at 4.6 µm and 6.5 µm nicely. --astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report

The Identification of CS2 and Evidence for Carbon-Sulfur Chemical Coupling in a Warm Giant Exoplanet Atmosphere

by Keith CowingApril 17, 2026April 17, 2026

Transmission spectroscopy with the James Webb Space Telescope (JWST) is revealing growing chemical complexity in giant exoplanet atmospheres. Of particular interest is sulfur, which had essentially no observational constraints before […]

Best-fit white light (5.06–10.55 µm) curves of HD 3167 b’s secondary eclipse from our SPARTA (blue), Eureka! (red), and exoTEDRF (green) reductions. (Top) Binned raw white light fluxes. The best-fit full SPARTA model (with integration-level x decorrelation), Eureka, and exoTEDRF models are shown alongside the quadratic ramp component shown as dashed lines. (Middle) Binned fluxes after dividing by the best-fit systematics model for each reduction. Retrieved eclipse depths and uncertainties are shown on the right. (Bottom) Binned residuals of the best-fit full models. For all plots, Eureka!/exoTEDRF data are offset by 0.001/0.002 days for visual clarity. -- astro-ph.EP

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Lava / magma ocean / Volcanic Worlds, Status Report

An Atmosphere On The Ultra-Short Period Super-Earth HD 3167 b

by Keith CowingApril 17, 2026April 17, 2026

‘Lava worlds’-Earth-sized planets hot enough (Teq >~ 1100 K) to melt their dayside silicate surfaces-have emerged as promising candidates for atmospheric detection and characterization. Thermal emission observations show an apparent […]

Effect of water dissolution on planetary radius (adapted from Luo et al (2024)). All interiors share identical bulk composition but differ in model assumptions. Classical models separated volatiles and refractories, and ignored melts (A). Alternative models that include melts but neglected volatile dissolution overestimate planetary radii (B). The water dissolution in the mantle (C) or mantle and core (D) reduces them. Scenario (D) is considered most realistic for hot super-Earths with magma oceans. -- astro-ph.EP

Exoplanets, -moons, -comets, Ice Giant, Status Report, Stellar Cartography

Origin And Characterization Of Super-Earths And Sub-Neptunes

by Keith CowingApril 15, 2026April 15, 2026

Super-Earths and sub-Neptunes represent the most common class of exoplanets discovered to date in our galaxy, yet they have no direct analogues in the Solar System. Since 2014, researchers within […]

A three-color image of the CygX region constructed from SPHEREx mosaics. In this image, blue is 1.13–1.19 μm, green is 2.9–3.20 μm (containing the H2O ice absorption feature), and red is 4.75–5.1 μm. Continuum emission from warm dust extends across the image, as evidenced by the extended orange clouds. Dark lanes are seen where the dust and H2O ice absorption are the strongest. Red sources appear in these dark lanes where there are background sources or embedded young stars shining through the dust. Blue stars are seen in regions with lower extinction or are foreground objects. -- The Astrophysical Journal

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release

Astrochemistry Update: SPHEREx Maps Vast Galactic Ice Regions

by Keith CowingApril 15, 2026April 15, 2026

NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) mission has mapped interstellar ice at an unprecedented scale.

This artist’s impression displays TRAPPIST-1 and its planets reflected in a surface. The potential for water on each of the worlds is also represented by the frost, water pools, and steam surrounding the scene. © NASA/R. Hurt/T. Pyle

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Between Eternal Night And Day, The Faces Of Two Cousins Of The Earth

by Keith CowingApril 14, 2026April 14, 2026

Red dwarf stars—cooler and smaller than our Sun—make up more than 75% of the stars in our Galaxy. Astronomers have shown that small, Earth-like planets are common around this type […]

Exoplanet 29 Cygni b, seen in this artist’s concept, is a gas giant weighing about 15 times the mass of Jupiter. It orbits a type A star (shown at upper right) slightly hotter and more massive than our Sun, at an average distance of 2.4 billion kilometres.-- Credit: NASA, ESA, CSA, J. Olmsted (STScI)

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Status Report, Stellar Cartography

Webb Redefines The Dividing Line Between Planets And Stars

by Keith CowingApril 14, 2026April 14, 2026

Planets, like those in our Solar System, form in a bottom-up process where small bits of rock and ice clump together and grow larger over time. But the heftier the […]

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

NCCR PlanetS: Observational And Computational Characterization Of Exoplanet Atmospheres

by Keith CowingApril 14, 2026April 14, 2026

This chapter reviews the current state of observational and theoretical efforts in the characterization of exoplanet atmospheres, with a focus on developments enabled through the Swiss National Centre for Competence […]

Pressure–temperature (P–T) conditions of our experiments compared to phase diagram of the CO2–H2O system. Red dots correspond to actual P–T conditions at various stages of ice preparation. Dashed lines are only indicative and do not correspond to measured variations in pressure. Paths labeled in red, yellow, and magenta correspond to ice retaining CO2. Paths labeled in black correspond to ice devoid of CO2. Lowercase letters show the stages of the experiment described in the text, with subscripts showing the applicable experiment number. The stars near the bottom left denote the P–T conditions during acquisition of spectra. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Europa, Icy Worlds, Imaging & Spectroscopy, Status Report

The Fate Of Frozen Carbonated Water At Europa-like Conditions

by Keith CowingApril 13, 2026April 13, 2026

We present the results of experiments probing the retention of CO2 in crystalline water ice, frozen sodium chloride (NaCl) brines, and flash-frozen carbonated water using diffuse reflectance infrared spectroscopy.

Wind structures for the synchronous and 10:1 SOR simulations, reproduced from fig. 5 of Part I and included here for reference. Columns from left to right show the horizontal distribution of zonal wind, meridional wind, and vertical wind at 0.001 bar. Streamlines indicate the direction of the horizontal flow. Results are shown in the heliocentric frame to more clearly illustrate the wind patterns. Black star-shaped markers indicate the location of the substellar point. The first and second rows show results from the synchronous and 10:1 SOR simulations as examples, with the wind patterns in other simulations being similar. -- astro-ph.EP

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

Three-dimensional Transport-induced Chemistry On Temperate Sub-Neptune K2-18b, Part II: The Combined Effects Of Atmospheric Dynamics And Chemical Reactions

by Keith CowingApril 12, 2026April 12, 2026

The upper atmospheres of temperate sub-Neptunes are strongly influenced by atmospheric dynamics due to their cool equilibrium temperature and thereby longer chemical timescales than the atmospheric dynamical timescales.

PSF-subtracted images of all targets. The observation subarray of each target is indicated. The first seven images are zoomed in to area of 11.0” × 11.0” for clearer view of the central regions. For the last three targets, the small size (4.4” × 4.4”) is due to the choice of the observation subarray. The location of the star PSF center is denoted by the white cross. Sources around LHS 1478, TOI-1468, and TOI-270 are labeled with letters, which are likely background sources. The arrow near HD 260655 indicates a low-S/N identification of possible close companion. We further examined this detection in Section 4.4. North is up and east is to the left. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

A Search For Wide-orbit Planets Around M-dwarfs Using Deep MIRI 15-micron Images

by Keith CowingApril 12, 2026April 12, 2026

Wide-orbit (>10 AU) gas giant planets shape the architecture of planetary systems, yet their occurrence rate remains poorly constrained.

JWST

The Identification of CS2 and Evidence for Carbon-Sulfur Chemical Coupling in a Warm Giant Exoplanet Atmosphere

An Atmosphere On The Ultra-Short Period Super-Earth HD 3167 b

Origin And Characterization Of Super-Earths And Sub-Neptunes

Astrochemistry Update: SPHEREx Maps Vast Galactic Ice Regions

Between Eternal Night And Day, The Faces Of Two Cousins Of The Earth

Webb Redefines The Dividing Line Between Planets And Stars

NCCR PlanetS: Observational And Computational Characterization Of Exoplanet Atmospheres

The Fate Of Frozen Carbonated Water At Europa-like Conditions

Three-dimensional Transport-induced Chemistry On Temperate Sub-Neptune K2-18b, Part II: The Combined Effects Of Atmospheric Dynamics And Chemical Reactions

A Search For Wide-orbit Planets Around M-dwarfs Using Deep MIRI 15-micron Images

Astrobiologist Dale Andersen’s Antarctic Field Report: 20 Oct 2026: Wheels Down In Cape Town

Astrobiology Primer

The Evolution Of Oxygen, Temperature, And Marine Aerobic Habitat For Animals Over The Last Billion Years Of Earth History

Icy Ocean Planet Recon: Saildrone Research Fleet To Circle Antarctica For 5 Years

Water As We’ve Never Known It: Testing Water Beyond Earth-like Conditions