M-dwarf Archives

Simulated emission spectra of GJ 3929 b for various surface (left) and atmospheric (right) compositions compared to the measured eclipse depths from our FN-PCA calculation,

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Mapping, Geodesy, Cartography, Bathymetry, Status Report

GJ 3929 b as the First Complete Rocky Worlds DDT Data Set

by Keith CowingJune 8, 2026June 26, 2026

Despite their large abundance, it is still unknown whether and under what conditions rocky planets around M dwarf stars can host atmospheres.

Comparison of input SEDs used in this study and molecular photoabsorption cross sections relevant to Archean-analog photochemistry. The horizontal bars indicate the FUV and NUV wavelength intervals used to compute the stellar FUV/NUV ratios in Figures 5 and 7. Top: Top-of-atmosphere (ToA) stellar energy fluxes at TRAPPIST-1 e from 120–350 nm for five SEDs: Peacock+2019 (P19) Median (orange) (S. Peacock et al. 2019), Mega-MUSCLES (W21) Adaptive (yellow), Mega-MUSCLES (W21) SEM (light blue) (D. J. Wilson et al. 2021), a “Revised PHOENIX” model (dark blue) constrained by the HST observations published in D. J. Wilson et al. (2021), and a scaled modern Sun (red) (G. Thuillier et al. 2004). All SEDs are scaled to TRAPPIST-1 e’s ToA irradiance. Bottom: Representative molecular cross sections for CH4 (pink), CO2 (black), H2O (green), O2 (light blue), and O3 (dark blue) are shown, highlighting the wavelength overlap between the cross sections and the stellar UV output. Where both the flux and the cross section are large, photolysis rates increase and influence production and loss pathways throughout the atmosphere. -- astro-ph.EP

Astronomy & 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

by Keith CowingJune 7, 2026June 7, 2026

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, […]

This artist's impression shows two Earth-sized worlds passing in front of their parent red dwarf star in the TRAPPIST-1 system 40 light-years away. Credit ESA/Hubble

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Press Release, Stellar Cartography

Red Dwarf Stars Detected ‘Eating’ Earth-like Planets

by Keith CowingMay 29, 2026May 29, 2026

Astronomers have found some of the strongest evidence yet that stars can swallow their own planets.

Schematic illustration of occurrence rate of inhabited planets versus observational detectability for JWST transmission spectroscopy

Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

The First Remotely Detected Biosignature May Not Be the Most Common: Implications for JWST and HWO

by Keith CowingMay 19, 2026May 19, 2026

The first detected member of a new astronomical class is often not representative of the underlying population, but instead reflects the selection effects of the observing technique that found it.

Habitable Zone diagram for the Ross 318 system. The green band indicates the Conservative Habitable Zone boundaries from Kopparapu et al. (2013). The orange star marks Ross 318; the violet circle marks Ross 318 b at a = 0.159 au with Seff = 0.58 S⊕. For comparison, the positions of Venus (0.72 au), Earth (1.00 au), and Mars (1.52 au) around the Sun are indicated. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Space Weather & Heliophysics, Status Report, Stellar Cartography

Detection and Characterization of the Temperate Super-Earth Ross 318 b

by Keith CowingMay 14, 2026May 14, 2026

Ross 318 is an M3.5V red dwarf exhibiting significant magnetic activity and a stellar rotation period of ∼ 51.5 d.

Super-Earths and sub-Neptunes - Grok via Astrobiology.com

Exoplanets, -moons, -comets, Press Release, Stellar Cartography

New Findings About Exoplanets Challenge Theories Of Planet Formation

by Keith CowingMay 1, 2026May 1, 2026

Astronomers estimate there is at least one planet for every star in our galaxy. Called exoplanets, they orbit stars outside our solar system. But new research from McMaster University reveals […]

Graphical Abstract. Created in BioRender. Liistro, E. (2026) https://BioRender.com/j2de4ay

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Plant Biology, Status Report

Is Constitutive Red-shift An Advantage For Oxygenic Photosynthesis Under M-dwarf Starlight? Insights From Acaryochloris marina sp. str. Moss Beach

by Keith CowingApril 29, 2026April 29, 2026

In the next years, several space missions will search for evidence of life on exoplanets, focusing on robust biosignatures associated with oxygenic photosynthesis, including atmospheric oxygen accumulation and the Vegetation […]

Starting from the top left corner and moving in a clockwise direction are the companions we detected to 2MASS J01283952-1458042, PM J02024+1034 A, 2MASS J05103956+2946479, 2MASS J07171706-0501031, 2MASS J10430293-0912410, and 2MASS J19445376-2337591. These reconstructed images sometimes contain a third “ghost peak” due to low SNR resulting in a lack of phase information. As noted in Section 3.1, the companions to 2MASS J05103956+2946479 and 2MASS J07171706-0501031 are unbound. -- astro-ph.SR

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

The POKEMON Speckle Survey of Nearby M dwarfs. IV. Distance-Limited Catalog (POKEMON-DLC)

by Keith CowingApril 29, 2026April 29, 2026

The Solar Neighborhood is dominated by stars smaller, colder, and fainter than the Sun: the M dwarfs.

WASP-39b transmission spectra and cloud scenarios. Spectra are observed with JWST (orange), HST (magenta), and VLT (green) in comparison to models with different Fe content: full IWF Graz cloud model (black line), Fe[s] replaced (dark gray), FeS[s] replaced (middle gray), and all Fe-binding materials replaced (light gray). The Fe-free mixed-material cloud compositions provide a good fit in the near-IR but not in the optical. — astro-ph.EP

Exoplanets, -moons, -comets, Gas Giants, Status Report

Exoplanet Climate Characterization With Transit Asymmetries

by Keith CowingApril 28, 2026April 28, 2026

Context. Space missions such as CHEOPS, JWST, and PLATO facilitate detailed characterization of exoplanets, particularly close-in gas giants and their wide range of global temperatures and climate regimes.

Black points are the sample of the planetary formation dataset provided by Kimura & Ikoma (2022) in the phase space of ∆a = 0.005AU, ∆Mp = 0.5M⊕. Two-dimensional probability density distribution of the initial water content and hydrogen-rich atmospheric mass for GJ 486b analogs, constructed using Gaussian kernel density estimation (KDE). The water content axis is sampled logarithmically and the atmospheric mass axis is sampled linearly to properly account for the dynamic range of the variables. The red overlaid ellipse represents the 3σ confidence region derived from the covariance matrix, indicating the principal dispersion of the sample distribution. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Inversion of Hydrogen-rich Atmosphere and Water Content for GJ 486b

by Keith CowingApril 23, 2026April 23, 2026

GJ-486b is a close-in planet orbiting an M dwarf and is therefore expected to have undergone strong atmospheric escape. Motivated by theoretical and observational studies on the constraints of its […]