[astro-ph.EP] Jupiter’s upper atmosphere provides a real-world laboratory for validating first-principles models of giant gaseous exoplanets and for constraining the key physical processes that govern them.
atmosphere
![Average ion velocity and magnetic field distributions near the ICB. (A) The center-of-mass velocity of heavy ions in the XZMSE plane, averaged over −1 RM < YMSE < 1 RM. (B) Proton velocity. (C) Velocity shear between protons and heavy ions. (D) Magnetic field strength. (E) Angle between the magnetic field and the X�⃗ MSEin the YZMSE plane, averaged over −1.5 RM < XMSE < 0.5 RM. Black arrows in (A) to (C) indicate velocity directions. Black curves in (A) to (D) mark the nominal locations of the bow shock and ICB. The black shaded sphere in (E) denotes the planetary shadow. -- [physics.space-ph]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Simultaneous.png?resize=1200%2C720&ssl=1)
Posted inSpace Weather & Heliophysics
Simultaneous Mars-orbit Observations Reveal Kelvin-Helmholtz Instability-driven Bulk Atmospheric Ion Escape
[physics.space-ph] Atmospheric ion escape driven by the solar wind is a key process controlling the long-term loss of the Martian atmosphere. Localized plasma clouds can carry substantial fluxes of planetary […]
![[LEFT]: Schematic of the star–planet–observer geometry defining the phase angle α, measured between the star–planet and planet–observer directions. The hemisphere of the planet facing the star is fully illuminated (gold) at all times, while the opposite hemisphere remains in shadow. The observer sees only the portion of the illuminated hemisphere that is visible at a given α, with full illumination visible only at α = 0◦. [RIGHT]: Illustration of planetary phases along an edge-on orbit, with the star at the center and the observer direction indicated below the orbit. Although the star-facing hemisphere remains illuminated throughout the orbit, the visible fraction of this hemisphere changes with phase angle. Full phase occurs at α = 0◦, quadrature at α = 90◦, and new phase at α = 180 , with gibbous and crescent phases spanning the intermediate ranges. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Impact.png?resize=1200%2C714&ssl=1)
Posted inAstronomy & Telescopes
The Impact of Planetary Phase Functions On Exo-Earth Detectability With EXOSIMS
[astro-ph.EP] The under-development NASA Habitable Worlds Observatory (HWO) aims to provide breakthroughs in exoplanet science, yet the most effective approaches to modeling the detection and characterization of potentially Earth-like worlds […]
Posted inExoplanets, -moons, -comets
ESCAPE: A Small Explorer Mission To Study The Stellar Drivers Of Exoplanet Evolution
[astro-ph.EP] The long-term stability of exoplanetary atmospheres depends critically on the extreme-ultraviolet (EUV) photon and high-energy particle fluxes from the host star, which are poorly constrained.
![Left: Orbital separations of inspiralling planets over time. Right: Mass accreted onto planets over time. For each initial planet mass, we show results for 𝜀 ∈ [0.01, 0.1, 0.3, 0.5, 1.0], with an increasing efficiency denoted by an increasing opacity. We also allow the accretion to increase up to 10× the Eddington limit, denoted by the dotted lines. Accretion stops when 𝑅𝐵 < 𝑅Jup (see §2.3). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Atmospheric-Signatures.png?resize=1200%2C722&ssl=1)
Posted inExoplanets, -moons, -comets
Atmospheric Signatures of Common Envelope Evolution in White Dwarf Planets
[astro-ph.EP] The majority of confirmed exoplanets orbit within 1 au of a main-sequence (MS) star. When their stellar hosts evolve off the MS, many of these planets will be engulfed […]
Posted inVenus
Development Of A Data Retrieval Algorithm For Venus Nephelometry In Preparation For The Rocket Lab Mission To Venus
[Science Direct] The Rocket Lab Mission to Venus (RLMV) will carry a single primary instrument, the Autofluorescence Nephelometer (AFN), to interpret atmospheric particle properties from light-scattering measurements. This process is […]
![Retrieved emission spectra (blue regions) plotted with the true planet’s flux from our forward model (red) for each redox state considered (IW-6 to IW+6). The retrieved spectra denser region represents the 1𝜎 confidence level, intermediate region 2𝜎, thin region the 3𝜎 level. The observational noise from LIFEsim is shown as a gray envelope. The retrieved spectra capture most spectral features in observed planets, especially in the more pronounced oxidised cases (bottom row). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Characterizing-the.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
Characterizing The Oxidation State Of Rocky Exoplanets With The Large Interferometer For Exoplanets (LIFE)
[astro-ph.EP] The oxidation state of rocky exoplanets is expected to play a fundamental role in shaping the chemical composition of their secondary atmospheres by influencing the chemical composition of volcanically […]
![Stellar influence on planetary habitability. Figure credit: solar images from NASA/ESA and KPNO/NSO/AURA/NSF, background pictures generated through OpenAI’s image-generation system (i.e., Adobe Firefly and ChatGPT Images 2.0). Illustration: K. Herbst - [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/StellarActivity.jpg?resize=1200%2C720&ssl=1)
Posted inHabitable Zones
Stellar Activity, Exoplanet, Habitability, Planetary Atmospheres
[astro-ph.EP] This chapter will review the deep connection of planetary habitability and stellar irradiation. We present the long-term stellar evolution as one of the drivers of atmospheric escape and climate […]
Posted inSETI & Technosignatures
Nondetection of Narrowband Radio Technosignatures from LHS 1140 b at 1–12 GHz
[Research Notes of the AAS] LHS 1140b, a rocky exoplanet in its host star’s habitable zone, was recently shown to have an escaping helium atmosphere.
![Geometrical and structural layout of the 12-km-thick Martian atmosphere and the 2-m-thick Martian regolith in GEANT4 simulations.-- [physics.ins-det]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Unveiling.png?resize=1200%2C718&ssl=1)
Posted inMars
Unveiling Neutron And Gamma Spectrum At Martian Surface In Presence And Absence Of Hydrogen: A Computational Study Based On GEANT4 Simulations
[physics.ins-det] Motivated by the interactions of the GCR protons with the Martian atmosphere and regolith in the absence and presence of hydrogen, a series of GEANT4 simulations are employed in […]