![The black line shows the empirical high-S/N template spectrum of Proxima Centauri (left) and Barnard’s Star (right). In the top panel, the green curve shows the median spectrum obtained by taking the median flux at each wavelength across the full grid of PHOENIX M-dwarf spectra, while the shaded region denotes the corresponding 1σ envelope. Comparing this range of model spectra with the empirical M-dwarf spectra demonstrates that the PHOENIX models do not adequately reproduce the observed spectra. The middle and bottom panels show either empirical templates or postellar spectral samples constructed from synthetic SPIRou observations of the respective stars at different S/N regimes. For the postellar spectra, the 1σ, 2σ, and 3σ intervals are shown, highlighting the uncertainties recovered on individual spectral feature. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/POSTELLAR.png?resize=1200%2C721&ssl=1)
[astro-ph.EP] We present a novel approach to perform posterior sampling of the underlying stellar spectrum in high-resolution spectroscopic observations.
PHOENIX
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
HD 143811 AB b: A Directly Imaged Planet Orbiting a Spectroscopic Binary in Sco-Cen
We present confirmation of HD 143811 AB b, a substellar companion to spectroscopic binary HD 143811 AB through direct imaging with the Gemini Planet Imager (GPI) and Keck NIRC2.
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Europa, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Stellar Cartography
Life After Death: Europa In The Evolving Habitable Zone Of A Red Sun
Most stars end their main-sequence (MS) lives by evolving through the red-giant and asymptotic-giant branches before ending as a quiescent, stable white dwarf. Therefore, it is imperative to model the […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Press Release
Weird New Planet Retained An Atmosphere Despite Its Nearby Star’s Relentless Radiation
A rare exoplanet that should have been stripped down to bare rock by its nearby host star’s intense radiation somehow grew a puffy atmosphere instead—the latest in a string of […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report
The PEPSI Exoplanet Transit Survey (PETS). V: New Na D Transmission Spectra Indicate A Quieter Atmosphere On HD 189733b
Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds.