[astro-ph.EP] Transmission spectroscopy increasingly reduces exoplanet spectra to derived compositional metrics, such as C/O, O/H, and mean molecular weight (MMW), but these quantities do not carry molecular abundance uncertainties in […]
Transmission spectroscopy
![Transmission spectra of TRAPPIST-1 c from the four JWST/NIRSpec PRISM epochs (4-pixel bins, 0.8–5.0 𝜇m), offset vertically by 200 ppm per epoch for clarity and colour-coded by date, with the inverse-variance-weighted mean spectrum (black, plotted at its true depth). Grey bands mark the stellar H2O features near 1.4 and 1.85 𝜇m. The dotted line marks 2.0 𝜇m, the boundary of the region where the contamination is strongest (Section 3). The 2023 November 8 visit contains a flare during transit and the 2024 July 9 visit shows activity outside transit (Section 2.5). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detecting.png?resize=1200%2C716&ssl=1)
Posted inAstronomy & Telescopes
Detecting Atmospheres In The Presence Of Stellar Contamination: An Empirically Calibrated Framework Applied To Four JWST/NIRSpec PRISM Transits Of TRAPPIST-1c
[astro-ph.EP] Transmission spectroscopy of rocky exoplanets orbiting late M dwarfs is limited by stellar contamination rather than photon noise.
Posted inExoplanets, -moons, -comets
WINERED Detects a Strong Atmospheric Outflow on the Sub-Neptune GJ 3090b
[astro-ph.EP] Sub-Neptunes are the most common short-period (P<100 d) planets known. A major goal for the field is to build a comprehensive understanding of their compositions and evolutionary histories, and […]
Posted inExoplanets, -moons, -comets
JWST Transmission Spectroscopy Of TOI-3235 b: Challenges In Constraining Giant Planet Atmospheres Around M Dwarfs Amid Stellar Contamination
[astro-ph.EP] Giant planets orbiting low-mass M dwarfs challenge current planet formation theories, which predict that such planets are unlikely to form. Characterizing their atmospheres can provide key insight into their […]
![Vertical profiles of temperature and volume mixing ratios for the species included in our atmospheric model, simulated for TRAPPIST-1 e. The profile behavior follows from the equations and assumptions described in Section 2.2. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Biosignature-Detectability.png?resize=1200%2C720&ssl=1)
Posted inBiosignatures & Paleobiology
Biosignature Detectability On Transiting Habitable Worlds With ELT/ANDES
[astro-ph.EP] The search for life beyond the Solar System is at a turning point, transitioning from theoretical predictions to observations enabled by next-generation observatories.
![Best-fitting spectrum and atmospheric properties of WD 1856 b. a. Spectral decomposition illustrating the model components required to explain WD 1856 b’s JWST transmission spectrum (FIREFLy reduction; orange circles with 1 σ error bars). The best-fitting model (black curve) contains absorption from multiple CH4 features (purple shading), H2 + He continuum absorption (dark grey shading), and tentative evidence of C2H6 near 3.4 µm (brown shading) and PH3 near 4.3 µm (orange shading). Aerosol continuum opacity (silver shading) blocks thermal emission from the deep atmosphere in windows between CH4 bands, obscuring the ‘negative spikes’ that would otherwise be observed near 0.7 µm, 2.9 µm, and longwards of 4.0 µm for a clear atmosphere. The best-fitting model without nightside thermal emission (blue dashed curve) cannot explain the significantly lower transit depths longwards of 3.5 µm. b. Retrieved atmospheric properties, planetary mass, and aerosol properties from WD 1856 b’s JWST transmission spectrum for the FIREFLy (orange histograms) and Juniper (green histograms) data reductions. The median (solid line) and 1 σ credible intervals for each parameter (dashed lines) are overlaid. c. Residuals between the data and best-fitting model. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Aerosols.png?resize=1200%2C719&ssl=1)
Posted inAtmospheres, Climate, Weather
Aerosols And Hydrocarbons In The Atmosphere Of A White Dwarf Planet
[astro-ph.EP] Most stars, including our Sun, will one day evolve into red giants and, subsequently, white dwarfs. Several planet candidates have recently been identified orbiting white dwarfs, demonstrating that planets […]
Posted inUncategorized
An Empirical Determination Of The Cosmic Shoreline
The cosmic shoreline concept was introduced to separate planets with atmospheres from those without, by relating the cumulative X-ray and extreme-ultraviolet (XUV) instellation (integrated over the planet’s lifetime) to the […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release, Space Stations
The Capability Of CSST In Characterizing Planetary Atmospheres. I. Transmission Spectroscopy Of Hot Jupiters
Transmission spectroscopy has become a primary tool for probing exoplanetary atmospheres, enabling constraints on their chemical compositions and providing limited information on their thermal properties.
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Photochemical CS2 Gas Detected On A 20-Myr-old Exoplanet
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.
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Optical Transmission Spectrum Of HAT-P-47b: Evidence For Aerosols And Tentative TiO Absorption
Transmission spectroscopy enables the characterization of exoplanet atmospheres by probing absorption features in their terminator regions.