![Orbital trajectories of two example scattering experiments. Left: An interaction that results in a free-floating planet-moon pair. Right: An interaction that results in a free-floating planet and a separate free-floating moon. The starting points of the bodies are indicated by the black dots. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Planet-moon.png?resize=1200%2C720&ssl=1)
[astro-ph.EP] Free-floating planet-moon pairs (FFPMs) may form when planetary systems experience close stellar encounters.
astro-ph.EP
Posted inComets and Asteroids
The Polana-Eulalia Complex with JWST NIRSpec: Connections to Bennu, Ryugu, and Outer Solar System Bodies
[astro-ph.EP] Carbon rich [C complex] asteroids provide insight into the early Solar System, and families of C complex asteroids serve as robust samples for learning about the internal structure of […]
Posted inStellar Cartography
TESS Photometry and Radial Velocity Analysis of the sub-Neptune Exoplanet π Mensae c and the Wider π Mensae Planetary System
[astro-ph.EP] Exoplanet characterization relies on precise measurements of planetary orbital and physical parameters. This is particularly important for planetary dynamics and atmospheric evolution, as orbital parameters help constrain system evolution, […]
Posted inExoplanets, -moons, -comets
Growing Planets Produce Extreme Dust Signatures
[astro-ph.EP] Collisions between planetary bodies are essential to the assembly of rocky planets like the Earth, but they are extremely difficult to observe. We therefore rely on indirect signatures of […]
![Models of mass-loss rate, outflow temperature, and H:He ratio for LHS 1140b in 2024. (A) Models of atmospheric mass-loss rate as a function of outflow temperature, 𝑇wind. Color indicates the normalized likelihood calculation, where zero corresponds to the maximum likelihood. Black contours indicate 1𝜎 and 3𝜎 derivations from the maximum likelihood. Data points with 1𝜎 error bars are the best-fitting values from the MCMC analysis of the 2024 spectrum of LHS 1140b, assuming an SED normalized to GJ 699 (black) or GJ 1132 (green). All models assumed the GJ 1132-normalized SED and fixed 𝑣wind the best-fitting value from the MCMC analysis. The dashed gray line shows a theoretical upper limit on the escape rate (see text). The dashed red line shows the theoretical minimum escape rate required to drag atomic oxygen in the outflow. The dashed black and green lines show the energy-limited escape rates calculated with the SEDs normalized by GJ 699 and GJ 1132, respectively. (B) Same as panel A, but as a function of the H:He ratio. Data points with dotted error bars assumed 10 times higher stellar XUV flux. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Helium-escaping.png?resize=1200%2C711&ssl=1)
Posted inHabitable Zones
Helium Escaping From The Atmosphere Of A Nearby Rocky Exoplanet Orbiting In A Habitable Zone
[astro-ph.EP] Observations of highly irradiated gas giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky exoplanets, perhaps because they have already escaped.
![The lifetime of the system with respect to the innermost orbit P1 is plotted on a logarithmic scale for two Luna-mass moons. Alongside the maximum eccentricity reached by each moon is plotted (color-coded). The black-dashed line marks the βmax calculated earlier in the Eqn. (5). The gray dashed lines and labels indicate the MMR locations predicted using Eqn. (15). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Tidal-evolution.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
Tidal Evolution Of Packed Moon Systems Around An Earth-mass Planet
[astro-ph.EP] While missions have long targeted terrestrial exoplanets within the habitable zone of their host stars, the number of exomoon candidates is expected to grow as next generation space-based observatories […]
![Schematic of the coupled interior-atmosphere evolutionary framework PROTEUS, showing the links between interior, surface, atmosphere, and stellar modules. Core components include SPIDER (mantle dynamics), CALLIOPE (surface in-/outgassing), AGNI/JANUS (radiativeand prescribed-convective atmospheres), ZEPHYRUS (atmospheric escape), and MORS (XUV stellar evolution). Modules exchange energy fluxes at each planetary interfaces—including core cooling, volatile outgassing, heat transport, heat loss to space, escape and stellar irradiation—while C–H–O–N–S volatiles are tracked throughout the mantle and atmosphere. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Atmospheric-evolution.png?resize=1200%2C718&ssl=1)
Posted inAtmospheres, Climate, Weather
Atmospheric Evolution Through Outgassing And Escape On Young Molten Rocky Exoplanets
[astro-ph.EP] The earliest rocky planet atmospheres are shaped by competition between initial volatile inventories and atmospheric escape. On young magma ocean planets, outgassing competes with atmospheric escape, controlling volatile retention […]
Posted inAstronomy & Telescopes
The Exozodi Spectral Effect: Residual Habitable Zone Dust May Bias ExoEarth Characterization
[astro-ph.EP] All exoplanetary systems are expected to host exozodiacal dust, or exozodi, originating from planetesimals. For many stars, exozodi will likely be the largest source of astrophysical noise in direct […]
Posted inExoplanets, -moons, -comets
Sulfur Photochemistry Observationally Traces Mantle Redox States Of Rocky Planets
[astro-ph.EP] Volatile outgassing from planetary interiors controls the composition of rocky exoplanets’ secondary atmospheres. However, observations indicate that disequilibrium processes, such as photochemistry and vertical transport, can strongly alter the […]
Posted inHabitable Zones
The Expected Yield Of Venus Zone Terrestrial Planets From PLATO
[astro-ph.EP] The characterization of terrestrial exoplanets and the conditions that lead to divergent climate outcomes is a primary goal of exoplanetary science.