[astro-ph.EP] Recent JWST observations challenge the traditional ‘cosmic shoreline’ from both sides, revealing thick volatile atmospheres on the hottest close-in ‘lava worlds,’ where irradiation should drive the most extreme escape, […]
M dwarf
Posted inBiosignatures & Paleobiology
The Effects of M Star Age Dependent Ultraviolet Emission on Detecting and Interpreting Exoplanet Biosignatures
[astro-ph.EP] Given their abundance and observational advantages, M stars will arguably be the best candidates for characterizing and searching for biosignatures on terrestrial exoplanets in the near future.
Posted inAtmospheres, Climate, Weather
A Search for Helium in the Atmospheres of Three Sub-Neptunes and a Super-Earth Around M-dwarfs
[astro-ph.EP] Thousands of sub-Neptunes have been discovered mainly through space-based surveys such as Kepler and TESS. Their bulk compositions and internal structures are thought to reflect their formation and evolutionary […]
Posted inMagnetic Fields, Electromagnetism, bioelectricity,
Tidal Locking As A Negative Feedback On Earth-like Planetary Dynamos: Consequences For Magnetic Shielding And Habitability
[Astronomy & Astrophysics] We investigate how tidal locking affects the magnetic field generation and magnetospheric protection of Earth-like planets orbiting the habitable zone of M dwarfs.
Posted inSpace Weather & Heliophysics
Intense but Harmless: Exo-Space Weather Around an M Dwarf with a Single-Hemisphere Dynamo
[astro-ph.SR] M dwarfs are among the most promising host stars in the search for habitable exoplanets. However, their active atmospheres drive intense magnetic activity, including energetic flares and possibly coronal […]
Posted inPlant Biology
Is A Constitutive Red-shift An Advantage For Oxygenic Photosynthesis Under M Dwarf Starlight? Insights From Acaryochloris Marina sp. str. Moss Beach
[FEMS Microbes] In the next decades, space telescope missions will search for life evidence on exoplanets, focusing on robust biosignatures associated with oxygenic photosynthesis, including atmospheric oxygen accumulation and the […]
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 […]
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 […]
![Blackbody spectra derived from the 𝑇eff of the Dyson sphere candidates A to J throughout the wavelength range of 10 to 1000 microns together with the detection thresholds of telescopes Akari (Murakami et al. 2007), IRAS (Neugebauer et al. 1984), the ALMA 12∼m array6 and JWST/MIRI. In the case of JWST, both broadband imaging and spectroscopic limits (based on the LRS Slit or MRS7observations) are shown. In the case of JWST and ALMA, all limits refer to 5𝜎 confidence in 1 hour exposure time (where exposure times refer to observations per filter in the case of imaging; per band in the case of ALMA spectroscopy; per channel in the case of JWST/MIRI MRS spectroscopy and for the entire plotted wavelength range in the case of JWST/LRS spectroscopy). As can be seen, all candidates are detectable throughout some part of the wavelength coverage of JWST. The inset shows a zoom-in on the part of the spectral energy distribution that may be detectable with ALMA for four of the candidates (A, G, I and J). -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Project-Hephaistos-1.png?resize=1200%2C720&ssl=1)
Posted inSETI & Technosignatures
Project Hephaistos — III. Characterizing Anomalous Infrared Sources Identified As Dyson-sphere Candidates
[astro-ph.SR] The infrared-flux excess of stars harbouring Dyson spheres represent one potential technosignature of extraterrestrial intelligence.
![Images in the JWST/MIRI F560W, F1000W and F1500W filters (central wavelength ≈ 5.6, 10 and 15 𝜇m) of candidates D (first row) and E (second row). White stars mark the Gaia positions of the M dwarfs, which in both cases are seen to be located ≈ 1 arcsec from the centres of background galaxies. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Project-Hephaistos.png?resize=1200%2C720&ssl=1)
Posted inSETI & Technosignatures
Project Hephaistos — IV. James Webb Space Telescope Observations of Two Dyson Sphere Candidates
[astro-ph.GA] We report on JWST/MIRI imaging and spectroscopy of two M-dwarf stars previously singled out by project Hephaistos as potential Dyson-sphere candidates (their candidates D and E) due to the […]