exopshere Archives

Comparing CO2 exosphere to surface properties on Ganymede’s leading hemisphere. A) Vertical CO2 gas column density (unit of 1018 m−2 , this work, see also Fig. O.2); B) Depth of CO2-solid absorption band (Paper I); C) Central wavelength of CO2-solid absorption band (Paper I); D) Reflectance at 3.65 µm (Paper I); E) Central wavelength of H2O Fresnel peak (Paper I); F) Relative amplitude of the maximum reflectance between 3.5 and 4 µm (H2O interband amplitude, Paper I). The north pole of the leading hemisphere possesses the most red-shifted absorption band center of solid CO2, consistent with CO2 trapped in amorphous H2O ice (Paper I). It also has the higher reflectance at 3.65 µm and H2O interband amplitude, indicative of a higher density of facets in H2O ice for the photons (i.e., smaller grains and/or more internal defects and/or higher micro-roughness/porosity), and the most blue-shifted central wavelength of the H2O Fresnel peak due to a higher proportion of amorphous water ice (Mastrapa et al. 2009). -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Cryobiology, Ganymede, Icy Worlds, Jupiter, Status Report

A Patchy CO2 Exosphere On Ganymede Revealed By The James Webb Space Telescope

by Keith CowingSeptember 23, 2024September 23, 2024

Jupiter’s icy moon Ganymede has a tenuous exosphere produced by sputtering and possibly sublimation of water ice. To date, only atomic hydrogen and oxygen have been directly detected in this […]

Io, Europa, Ganymede, and Callisto. Credit: NASA/JPL/DLR

Biogeochemical Cycles & Geobiology, Callisto, Europa, Ganymede, Icy Worlds, Imaging & Spectroscopy, Io, Jupiter, Radiation, Status Report

Energy And Temperature Dependencies For Electron-induced Sputtering From H2O-ice: Implications For The Icy Galilean Moons

by Keith CowingMay 9, 2024May 9, 2024

To better assess the role that electrons play in exosphere production on icy-rich bodies, we measured the total and O2 sputtering yields from H2O-ice for electrons with energies between 0.75 […]

exopshere

A Patchy CO2 Exosphere On Ganymede Revealed By The James Webb Space Telescope

Energy And Temperature Dependencies For Electron-induced Sputtering From H2O-ice: Implications For The Icy Galilean Moons

Tricorder Tech: New Handheld Device Maps Chemical Composition Using Infrared Light

No Statistically Significant Evidence For A Correlation Between Stellar And planetary Composition

Water Planet Recon: How Accurately Can We Measure Earth Ocean’s Deepest Point?

Webb Reveals A Stunning Panorama Of Star Formation

Deep Learning of SHERLOC Raman Spectra For Facilitating Mars Astromaterial Identification