相关论文: Evolution of granular salty ice analogs for Europa…
Recent visible-wavelength observations of Europa's surface obtained with the Hubble Space Telescope revealed the presence of an absorption feature near 450 nm that appears spatially correlated with leading-hemisphere chaos terrain. This…
Europa's leading hemisphere chaos regions have a spectral feature at 450 nm that has been attributed to absorption by crystal defects in irradiated sodium chloride, known as F-centers. Some discrepancies exist between the laboratory data of…
Europa's surface composition and evidence for cryovolcanic activity can provide insight into the properties and composition of the subsurface ocean, allowing the evaluation of its potential habitability. One promising avenue for revealing…
Recent infrared observations at 1.5-4.0 $\mu m$ using large ground-based telescopes have suggested that Cl-bearing salts are likely present on Europa's surface as non-ice materials. The chemical compositions of those Cl-bearing salts are…
The Galileo Near Infrared Mapping Spectrometer (NIMS) collected spectra of Europa in the 0.7-5.2 $\mu$m wavelength region, which have been critical to improving our understanding of the surface composition of this moon. However, most of the…
Recent observations from the Hubble Space Telescope show a mid-UV absorption feature localized to leading hemisphere chaos regions on Europa. The same regions were previously found to have a visible absorption at 450 nm that was attributed…
Physical processing of Europan surface water ice by thermal relaxation, charged particle bombardment, and possible cryovolcanic activity can alter the percentage of the crystalline form of water ice compared to that of the amorphous form of…
We publish the first NIR spectra of grain particulate mixtures of water ice, epsomite, and halite at cryogenic temperatures. Furthermore, we perform a quantitative assessment of the ability of both intimately- and linearly-mixed models to…
We present maps of surface composition of Europa's anti-jovian hemisphere acquired using high spatial resolution IFU multi-spectral data from the SPHERE instrument on the Very Large Telescope (0.95 to 1.65$\mu$m) and the NIMS instrument on…
Recent laboratory efforts and telescopic observations of Europa have shown the relevance of a yellow colouration of sodium chloride (NaCl) caused by crystal defects generated by irradiation. We further investigate this process by…
Competing processes shape Europa's surface: geological activity replenishes material through resurfacing, while bombardment by charged particles alters surface chemical composition. Each process leaves distinct spectral signatures. We…
Europa's surface composition and physical characteristics are commonly constrained using spectral deconvolution through linear mixture (LM) modeling and radiative transfer-based (RT) intimate mixture modeling. Here, I compared the results…
We present hemispherically resolved spectra of the surface of Europa from ~3.1--4.13 microns, which we obtained using the near infrared spectrometer NIRSPEC on the Keck II telescope. These include the first high-quality L-band spectra of…
The composition of Europa's trailing hemisphere reflects the combined influences of endogenous geologic resurfacing and exogenous sulfur radiolysis. Using spatially resolved visible-wavelength spectra of Europa obtained with the Hubble…
We present mid-infrared SOFIA/EXES spectroscopy of Europa, seeking direct evidence of the presence of water vapor arising from plumes venting from the surface of Europa. We place quantitatively useful upper limits on the strength of water…
Thermal measurements constrain the physical properties of icy satellite surfaces, including grain size, porosity, and regolith structure. On Europa, analyses of the Galileo Photopolarimeter-Radiometer (PPR) dataset revealed thermal inertia…
Evidence for plumes of water on Europa has previously been found using the Hubble Space Telescope (HST) using two different observing techniques. Roth et al. (2014) found line emission from the dissociation products of water. Sparks et al.…
The surface of Europa experiences a competition between thermally-induced crystallization and radiation-induced amorphization processes, leading to changes of its crystalline structure. The non-linear crystallization and…
We present the results of experiments probing the retention of CO2 in crystalline water ice, frozen sodium chloride (NaCl) brines, and flash-frozen carbonated water using diffuse reflectance infrared spectroscopy. Characteristic absorptions…
The surface of Europa could contain the compositional imprint of a underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply…