GJ 1214 b Archives

Clouds may form via heterogeneous nucleation on top of ‘seed’ photochemical haze particles. Whether or not this pathway dominates over homogeneous nucleation—the process through which ‘pure’ clouds spontaneously form—depends on the microphysical contact angle between the relevant cloud and haze species. Smaller contact angles correspond to stronger cloud-haze interactions due to the increased affinity between the clouds and hazes. While this contact angle is unknown in the absence of lab data, heterogeneous nucleation is the primary cloud-formation pathway across the Solar System. -- [astro-ph.EP]

Wet Removal and Cloud Enhancement: The Microphysics of Cloud-Haze Interactions on Sub-Neptunes

by Keith CowingAugust 21, 2026August 21, 2026

[astro-ph.EP] Aerosols are a near-ubiquitous feature of sub-Neptune atmospheres, yet their microphysical nature remains poorly understood. Both condensate clouds and photochemical hazes have been proposed to explain observations, but have […]

Transmission spectrum of GJ 1214b using the 5% CH4-derived haze sample atmospheric composition. The sample from K84, G18/C23 C/O = 1 sample, and H24’s sample at 300 K are overplotted for reference. We include the observations from L. Kreidberg et al. (2014); E. M. R. Kempton et al. (2023b); E. Schlawin et al. (2024) with offsets for comparisons between models. The error bars account for 1σ uncertainties in the observations. Top: Spectra from 0.5 to 8 µm, where there are large differences in the resulting transmission spectrum between the sample and previous literature optical constants. Our samples pre- and post-irradiation produce largely flat spectra. Bottom: Spectra from 2 to 3 µm. We see slight changes between our preand post-irradiation transmission spectra, where our hazes are letting gaseous CO2 found in the simulated atmosphere to be more or less visible. -- astro-ph.EP

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

Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes

by Keith CowingJune 8, 2026June 8, 2026

Temperate sub-Neptune and terrestrial exoplanets could contain large inventories of water in various phases, such as water-dominated atmospheres or even oceans. Observations have shown that many exoplanets, including water worlds, […]

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 […]

Predicted relative transit depth change from the equilibrium chemistry CO2-only model retrieved for CRIRES+ data (green). The model predictions are plotted in high-resolution in the wavelength region overlapping with the CRIRES+ measurements indicated by the grey shaded areas and in low-resolution for the rest of the wavelength range. Space-based measurements from HST (blue) and JWST (orange) are also shown. The 1σ and 1.5σ uncertainties of the model are indicated as darker and lighter green shaded areas, respectively. We also mark the lower 1.1σ uncertainty boundary with a dotted green line as a potential match to the amplitude of the CO2 bump in the JWST measurements at 4200 nm. The HST-WFC3 and JWST NIRSpec G359H measurements were taken from the online data provided by Schlawin et al. (2024) containing the HST data adapted from Kreidberg et al. (2014).-- astro-ph.EP

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

Cloudy With A Chance Of Metals: Indications Of CO2 In The Atmosphere Of GJ 1214 b From High-resolution K-band Spectroscopy

by Keith CowingApril 19, 2026April 19, 2026

Sub-Neptune exoplanets frequently exhibit muted transmission spectra, with GJ 1214 b being the most prominent example. Following years of intense observing campaigns yielding featureless planetary spectra, recent observations with JWST […]

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Atmospheric Constraints On GJ 1214 b From CRIRES+ And Prospects For Characterisation With ANDES

by Keith CowingFebruary 19, 2026February 19, 2026

In this study, we aim to constrain the atmospheric composition of GJ 1214 b using all available transits observed with the upgraded CRIRES+ spectrograph at the VLT by searching for […]

Interior structure schematic for the interior composition of sub-Neptune models presented in this work. Color is an approximate indicator of temperature (specific values depend on the model). The envelope (∼5% by mass) is a mixture of hydrogen, helium, and heavy elements (Z) represented by either water (Section 3.1) or silicates (Sections 3.2, 3.3). The mantle composition is MgSiO3, and the core composition is Fe16Si. We maintain a 2:1 mass ratio between the core and the mantle. For this work, the EMB represents a steep compositional gradient and thus controls mantle cooling by transferring heat to the envelope via conduction. Since conductive flux alone is insufficient to transport the entire interior heat to the envelope, a steep temperature gradient forms at the EMB, as seen in all models in this work. -- astro-ph.EP

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

Sub-Neptune Memories I: Implications of Inefficient Mantle Cooling and Silicate Rain

by Keith CowingJanuary 12, 2026January 12, 2026

We explore the evolution of sub-Neptune (radii between ∼1.5 and 4 R⊕) exoplanet interior structures using our upgraded planetary evolution code, APPLE, which self-consistently couples the thermal and compositional evolution […]

A new study finds that many “mini-Neptunes”—perhaps the most common planets in the galaxy—are under so much pressure from their heavy atmospheres that the surface is likely compressed solid. Illustration courtesy NASA/JPL-Caltech/R. Hurt (IPAC)

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Lava / magma ocean / Volcanic Worlds, Press Release

Revising Our Understanding Of The Most Common Planets In Our Galaxy

by Keith CowingNovember 6, 2025November 6, 2025

As telescopes have become more powerful, it’s turned out our solar system is not the only game in town: There are millions of other planets out there in the galaxy.

Possible interior compositions of 55 Cnc e. Compositions consistent within the 1σ, 2σ, and 3σ M-R uncertainties are shown in orange, dark teal, and light teal, respectively. The red dashed and solid lines show xcarbon = 12 wt% and 24 wt%, respectively, the upper bounds of xcarbon assuming no volatile loss (E. A. Bergin et al. 2023). The blue curve shows interior solution from N. Madhusudhan et al. (2012), to the right of which are allowed values (1σ uncertainty). Ternary diagrams are shown for two radius assumptions: (a) visible radius, 2.04 ± 0.15 R⊕, and (b) gray radius, 2.20 ± 0.12 R⊕, following N. Madhusudhan et al. (2012). Our interior models with updated carbon and SiC EOSs are consistent with earlier studies. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Carbon-rich Sub-Neptune Interiors Are Compatible With JWST Observations

by Keith CowingAugust 22, 2025

Many possible interior compositions exist for sub-Neptunes: ice-poor, ice-rich, and water-dominated interiors can all match the measured masses and radii.

Modeled transit spectra of GJ 1214b including haze and graphite scenarios.

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Impact Of Organic Hazes And Graphite On The Observation Of CO2-rich Sub-Neptune Atmospheres

by Keith CowingAugust 14, 2025August 14, 2025

Many sub-Neptune and super-Earth exoplanets are expected to develop metal-enriched atmospheres due to atmospheric loss processes such as photoevaporation or core-powered mass loss.

Suppression index Ξ as a function of mantle thermal gradient ∆T and bulk modulus K. Regions with Ξ > 1.1 (light-shaded) correspond to > 10% enhancements in escape velocity, indicating strong thermoelastic suppression of atmospheric loss. -- astro-ph.EP

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

Thermoelastic Contraction As A Suppressor Of Atmospheric Escape In Close-in Exoplanets

by Keith CowingAugust 12, 2025

The long-term retention of substantial atmospheres in close-in exoplanets presents a major challenge to classical hydrodynamic escape theory, which predicts rapid mass loss under intense stellar irradiation.

GJ 1214 b

Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes

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

Cloudy With A Chance Of Metals: Indications Of CO2 In The Atmosphere Of GJ 1214 b From High-resolution K-band Spectroscopy

Atmospheric Constraints On GJ 1214 b From CRIRES+ And Prospects For Characterisation With ANDES

Sub-Neptune Memories I: Implications of Inefficient Mantle Cooling and Silicate Rain

Revising Our Understanding Of The Most Common Planets In Our Galaxy

Carbon-rich Sub-Neptune Interiors Are Compatible With JWST Observations

The Impact Of Organic Hazes And Graphite On The Observation Of CO2-rich Sub-Neptune Atmospheres

Thermoelastic Contraction As A Suppressor Of Atmospheric Escape In Close-in Exoplanets

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