![Keck/NIRSPEC M -band spectrum of TRAPPIST-1 (black) with best-fit model (red). Top: echelle order 16 (λ ≈ 4.63–4.73 µm). Bottom: order 15 (λ ≈ 4.93–5.04 µm). Residuals (data minus model) are shown beneath each panel. Gray shading indicates the relative telluric transmission (dimensionless, 0–1). Masked pixels are omitted from the retrieval. -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Isotopic.png?resize=1200%2C721&ssl=1)
[astro-ph.SR]. Elemental and isotopic abundances are key tracers of planet formation, stellar evolution, and Galactic chemical evolution. Very low-mass stars are particularly interesting in this regard, because unlike more massive […]
TRAPPIST-1
![Differences in the TLS effect for the TRAPPIST-1 planets for our minimal two-zone model. The left panel shows a representative diagram of the stellar surface with increased spottedness in the polar regions. Lines are drawn to represent the center of the transit chord for each of the TRAPPIST-1 planets. As a representative example, the width of planet b’s transit chord is shaded in blue. In the right panel, the relative transit depth is shown assuming only stellar heterogeneity made up of cooler regions (upper) and hotter regions (lower) with no contribution from a planetary atmosphere over the wavelength range relevant to JWST NIRSpec/PRISM. The higher impact parameter planets (f, g, and h) are less impacted by the TLS effect than the lower impact parameter planets given our choice of zonal boundary. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Leveraging-Impact.png?resize=1200%2C717&ssl=1)
Posted inTRAPPIST-1
Leveraging Impact Parameter to Mitigate the Transit Light Source Effect: Early Insights from TRAPPIST-1
[astro-ph.EP] Stellar activity complicates exoplanet transmission spectra, particularly for smaller planets around M dwarfs with JWST.
![Simulations of the external planets’ (d to h) contributions at the times of JWST observations (represented in color over the bare rocks total curve). Relative fluxes were simulated using the SPHINX spectrum at 12.8 microns. The contributions of each planet are shown in colored dotted lines and the case of all planets with thick atmospheres in dashed grey. The total phase curves correspond to the total contribution of the external planets. Eclipses are displayed but not transits. Visit 1 of GTO 1279 is not displayed as the observational strategy from this visit was different from the others and less precise (Ducrot et al. 2024) -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Looking.png?resize=1200%2C717&ssl=1)
Posted inTRAPPIST-1
Looking For TRAPPIST-1 External Planets’ Emission In JWST Archival Data
[astro-ph.EP] The TRAPPIST-1 system has been thoroughly observed with JWST. Unfortunately, stellar contamination issues strongly limit the interpretation of transit observations.
Posted inTRAPPIST-1
Atmospheric Reconnaissance of TRAPPIST-1 f with JWST NIRISS SOSS: No Evidence for the Transit Light Source Effect
[astro-ph.EP] In just over three years of operation, JWST has observed all seven planets of the TRAPPIST-1 system. The two innermost planets were found to have little to no atmosphere, […]
![Illustration of the TRAPPIST-1 system and the most recent JWST constraints on planetary atmospheres. Planet size and distance roughly to scale. - [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/veiled.png?resize=1200%2C820&ssl=1)
Posted inTRAPPIST-1
Veiled in Starlight: Impacts of Stellar Contamination On Retrievals of TRAPPIST-1f’s Atmospheric Composition
[astro-ph.EP] The TRAPPIST-1 system offers seven terrestrial exoplanets with tight orbits and large radii ratios to the host star. If an atmosphere exists, transmission spectroscopy can be used to detect […]
Posted inHabitable Zones
Quantifying Detection Bias And Recovering Habitable Zone Occurrence Rates In The NASA Exoplanet Archive
[Astronomy and Computing] Transit surveys tend to underestimate how often habitable zone (HZ) planets appear. The core reason is geometric: the chance that an Earth-like planet transits a sun-like star […]
![Retrieved temperature, mixing ratios, and haze parameters from all three retrieval set ups. Left: Retrieved volume mixing ratios for all three retrieval cases shown at the approximate depth of the haze layer. Right: Haze opacity in dashed lines and temperature in solid lines as a function of pressure and altitude. Where available we show the Teanby et al. (2006) mixing ratios and temperature profile. Despite varying assumptions and haze schemes, all retrievals indicate a haze layer in approximately the same pressure location. Note that the POSEIDON haze location is inferred from the pressure contribution functions and is shown as a shaded region. - [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Piercing-through.png?resize=1200%2C710&ssl=1)
Posted inExoplanets, -moons, -comets
Piercing Through The Haze: Characterizing Titan-like Terrestrial Exoplanets With JWST
[astro-ph.EP] As we enter a new era of using JWST to characterize exoplanet atmospheres, a top priority is defining observational needs and parameters in the search for life on an […]
Posted inAstronomy & 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
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, […]
Posted inAstrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Press Release, TRAPPIST-1, Water/Hycean Worlds & Oceanography
Interior-Atmosphere Coupling on TRAPPIST-1 f, g, and h: Cryovolcanic Water Exospheres and Infrared Detectability
We investigate the interior structures and cryovolcanic observability of the exoplanets TRAPPIST-1f, g, and h. Our aim is to determine which interior configurations can sustain subsurface liquid water oceans in […]
Posted inAstrochemistry, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Status Report, TRAPPIST-1
Coupled Photochemical-Climate Modeling of Plausible Tenuous Outgassed Atmospheres on the TRAPPIST-1 Planets
Available JWST observations TRAPPIST-1 system have suggested that several of the planets are likely airless, or possess a very tenuous atmosphere.