![The timescale required for a 10 M⊕ring of planetesimals around a 1 M⊙ star to radially diffuse 0.1 M⊕ into the inner 0.5 au. The planetesimal density is assumed to be 4 g cm−3 . The black dashed line shows the boundary where the inner edge is just reachable by the radially diffusing disk, below which the escape velocity is less than the critical escape velocity (v0.5au) and planetesimals are not deliverable at this level. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Substructure.png?resize=1200%2C715&ssl=1)
[astro-ph.EP]. Motivated by recent observations suggesting rings found in debris disks are wider than those in protoplanetary disks, we consider a picture in which planetesimals formed in radially narrow dust […]
astro-ph.EP
Posted inMars
Quasi-diurnal Kelvin Wave Observed in the Atmosphere of Mars by the Pressure Sensor on the InSight Lander
[astro-ph.EP]. During the initiation phase of Martian dust storms, a spectral signature of a zonal wavenumber 1 normal mode Kelvin wave (K1) has been observed in several surface pressure records.
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 inExoplanets, -moons, -comets
Finding Habitable Exoplanets with Binary Relative Astrometry: Planet Detection and Characterization with the Microarcsecond Astrometric Retrieval Algorithm (MARA)
[astro-ph.EP] Binary relative astrometry is a technique to search for rocky planets in the habitable zone of nearby binary stars using 1D relative astrometry at the microarcsecond level.
![Example of the stacking procedure for the Maidanak data obtained on 2025 August 15, based on ten 60 s exposures in each of the B, V , and R filters. Left: Comet-centered stack, showing the coma morphology without trailing of the comet signal. The pink circle indicates an aperture radius of 10 000 km. Right: Sidereal stack used for photometric calibration, in which the comet appears trailed.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Inbound.png?resize=1200%2C720&ssl=1)
Posted inComets and Asteroids
The Inbound Gas and Dust Evolution of Interstellar Comet 3I/ATLAS from Optical Spectroscopy and Multi-band Photometry
[astro-ph.EP] Interstellar objects (ISOs) provide direct constraints on the composition and evolution of extrasolar planetary systems. As the third confirmed ISO, comet 3I/ATLAS offers a rare opportunity to study pristine […]
![HZ and planetary orbits in the GJ 12 system. The extent of the HZ is shown in green, where light green and dark green indicate the CHZ and OHZ, respectively. The solid line shows the orbit with the nominal eccentricity of 0.24, and the dashed lines represent 1σ boundaries (Turner et al. 2026). The scale of the figure is 0.2 AU along each side with a 0.02 AU grid.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Tidal-.png?resize=1200%2C712&ssl=1)
Posted inExoplanets, -moons, -comets
The Tidal Venus Phenomenon: Demographics and Case Studies
[astro-ph.EP] The demographics of terrestrial planets and their orbits reveal a vast diversity in overall planetary energy budgets.
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 […]
![(Top) Measured OC albedo values from Goldstone (from Table 4) and (bottom) measured OC albedo values from the GBT (from Table 5). The horizontal dashed lines indicate the weighted means of the albedos, which is 0.90 for Goldstone and 0.80 for GBT. The error bars on our albedo values are taken to be the total uncertainty calculated in Section 4. The color bar on the right shows the dates of our observations in YYMMDD. The x-axis is the subradar point west longitude. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Radar-observations.png?resize=1200%2C751&ssl=1)
Posted inEuropa
Radar Observations Of Europa in 2011-2024: New Insights Into Radar Scattering Properties
[astro-ph.EP] Three of Jupiter’s Galilean satellites – Europa, Ganymede, and Callisto – are of particular scientific interest due to their icy shells and suspected subsurface oceans. However, the radar properties […]
Posted inStellar Cartography
A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: III. Characterization of the Cold Imaged Planet Hosts AF Lep A and ε Indi A
[astro-ph.EP] JWST has enabled the measurement of carbon, oxygen, and sulfur abundances in the atmospheres of directly imaged planets. Interpretation of these abundances from a planet formation standpoint requires the […]
Posted inHabitable Zones
The Viability of Life in Helium-Dominated Exoplanet Atmospheres
[astro-ph.EP] Helium is the second most abundant element in the Universe, yet helium-dominated atmospheres are rarely considered as environments for life.