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Clay sediments derived from fluvial activity in and around Ladon basin, Mars
Weitz, Catherine M.; Wilson, Sharon A.; Grant, John A. +5 more
The morphology and mineralogy of light-toned layered sedimentary deposits were investigated using multiple orbital datasets across the Ladon basin region, including within northern Ladon Valles, southern Ladon basin, and the southwestern highlands of Ladon basin. Light-toned layered deposits are particularly widespread in Ladon Valles and Ladon ba…
High-resolution DTM-based estimation of geomorphometric parameters of selected putative martian scoria cones
Székely, Balázs; Vörös, Fanni
Some previous studies have identified a number of features on Mars that are thought to be scoria cones. Since (terrestrial) scoria cones have special significance that they are monogenetic volcanoes, i.e. the volcanic edifice is created by a single eruptive event. The process usually produces fairly symmetrical cones, making them a target for morp…
Modeling the complete set of Cassini's UVIS occultation observations of Enceladus' plume
Esposito, Larry W.; Portyankina, Ganna; Aye, Klaus-Michael +2 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a plume of water vapor spewing out from the south polar regions of Enceladus via occultations 7 times during the Cassini mission. Five of them yielded spatially resolved data that allowed fits to a set of individually modeled jets. We created a direct simulation Monte Carlo (DSMC) model …
Geology of the Crüger-Sirsalis Basin: Evidence for prolonged volcanism in the southwestern near side of the Moon
Bhatt, Megha; Bhardwaj, Anil; Srivastava, Neeraj +1 more
The Pre-Nectarian Crüger-Sirsalis Basin (centered at 16.0°S, 293.0°E; ~ 475 km in diameter) is a primarily degraded and obscured impact basin on the Moon. This study presents the first geological description of the Crüger-Sirsalis Basin using remote sensing datasets from Lunar Reconnaissance Orbiter (LRO), Chandrayaan-1, and Kaguya missions. An in…
The stability of a liquid-water body below the south polar cap of Mars
Ruiz, Javier; Bramson, Ali M.; Egea-González, Isabel +4 more
Radar data from the Mars Express spacecraft show bright subsurface reflections in the Planum Australe area that could be due to liquid water located at a depth of 1.5 km (Orosei et al., 2018). If this interpretation of the data is correct, the presence of such water would have important implications for the present-day thermal state of the region.…
Invited review: Infrared spectroscopy of planetary atmospheres: Searching for insights into their past and present histories
Encrenaz, Thérèse
This article reflects my personal experience and illustrates some developments in the field of planetary spectroscopy, achieved within the Planetology Group of Paris Observatory over the past fifty years. Over these decades, planetary spectroscopy has led to the identification of minor atmospheric species with mixing ratios as low as a few parts p…
Astrometric observations and analysis of Triton during 2013-2019
Zhang, H. Y.; Yan, D.; Qiao, R. C. +2 more
Triton is the largest irregular satellite of Neptune. A total of 1135 new observed positions of Triton in the period 2013-2019 were collected by the 1.0 m telescopes at Yunnan Astronomical Observatory of CAS during 13 nights. These positions of Triton were obtained based on Gaia DR2 catalogue. We compared our observations to the theoretical positi…
Molecular hydrogen in the upper atmospheres of Saturn and Titan
Strobel, Darrell F.
Molecular hydrogen is the third most abundant species in Titan's atmosphere with a tropospheric/lower stratospheric mole fraction of 0.001 derived from Voyager and Cassini measurements and the major species in Saturn's atmosphere. The motivation for this paper is to explore the hypothesis that the corrected H2 density measurements repor…
Early Noachian terrains: Vestiges of the early evolution of Mars
Dohm, James M.; Buczkowski, Debra; Anderson, Robert C. +1 more
NASA's main scientific reason for exploring Mars is to determine the early evolution and the possibility of life on the red planet. Scientists have adopted an approach for identifying habitable environments on Mars that could be conducive to the early development and preservation of life (e.g., robotically exploring hydrothermal and lake deposits …
Venus mountain waves in the upper atmosphere simulated by a time-invariant linear full-wave spectral model
Schubert, Gerald; Navarro, Thomas; Walterscheid, Richard L. +1 more
A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus' atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from …