Search Publications
Surface Properties of Near-Sun Asteroids
Richardson, Derek C.; Sunshine, Jessica M.; Hsieh, Henry H. +8 more
Near-Earth asteroids (NEAs) with small perihelion distances reach subsolar temperatures of ≥1000 K. They are hypothesized to undergo "supercatastrophic" disruption, potentially caused by near-Sun processes such as thermal cracking, spin-up, meteoroid impacts, and subsurface volatile release, all of which are likely to cause surface alteration, whi…
Winter Weakening of Titan's Stratospheric Polar Vortices
Toigo, A. D.; Teanby, N. A.; Newman, C. E. +3 more
Polar vortices are a prominent feature in Titan's stratosphere. The Cassini mission has provided a detailed view of the breakdown of the northern polar vortex and formation of the southern vortex, but the mission did not observe the full annual cycle of the evolution of the vortices. Here we use a TitanWRF general circulation model simulation of a…
Pre- and Post-entry, Descent and Landing Assessment of the Martian Atmosphere for the Mars 2020 Rover
Kleinböhl, Armin; Mischna, Michael A.; Lewis, Stephen R. +10 more
This review provides an analysis of activities undertaken by the Mars 2020 Council of Atmospheres (CoA) in support of the entry, descent, and landing (EDL) of the Mars 2020 rover Perseverance in Jezero crater, Mars. The activities of the CoA were designed to evaluate the safety of early-stage landing site candidates and, later, to constrain the ra…
Observations and Modeling of the Opposition Surges of the Icy Moons of Saturn Based on Cassini Visual Infrared Mapping Spectrometer Data
Buratti, B. J.; Hendrix, A. R.; Dalba, P. A. +5 more
Observations of the opposition surges on the main moons of Saturn (Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus) during Cassini's prime and extended missions are reduced and analyzed. The main data set comes from the Visual Infrared Mapping Spectrometer (VIMS) with wavelength coverage in the visible and near-infrared out to 3.60 µm, co…
Local-time Dependence of Chemical Species in the Venusian Mesosphere
Shao, Wencheng D.; Zhang, Xi; Mendonça, João +1 more
Observed chemical species in the Venusian mesosphere show local-time variabilities. SO2 at the cloud top exhibits two local maxima over local time, H2O at the cloud top is uniformly distributed, and CO in the upper atmosphere shows a statistical difference between the two terminators. In this study, we investigated these loca…
Titan Stratospheric Haze Bands Observed in Cassini VIMS as Tracers of Meridional Circulation
Le Mouélic, S.; Rodriguez, S.; Sotin, C. +9 more
We analyzed Cassini data to derive the nature and evolution of circumglobal annuli observed in the stratosphere of Titan, Saturn's largest moon. The annuli were observed between 2004 and 2017 in data acquired by the Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft. We observed a north polar annulus, an equatorial annulus, a…
Uranus's and Neptune's Stratospheric Water Abundance and Vertical Profile from Herschel-HIFI
Irwin, P. G. J.; Teanby, N. A.; Nixon, C. A. +2 more
Here we present new constraints on Uranus's and Neptune's externally sourced stratospheric water abundance using disk-averaged observations of the 557 GHz emission line from Herschel's Heterodyne Instrument for the Far-Infrared. Derived stratospheric column water abundances are × 1014 cm‑2 for Uranus and ×1014 cm
Planet Four: Derived South Polar Martian Winds Interpreted Using Mesoscale Modeling
Schwamb, Megan E.; Michaels, Timothy I.; Lintott, Chris J. +3 more
For the first time, model-derived and imagery-derived wind directions and speeds have been compared in Mars's south polar region. Seasonal fan-shaped deposits are routinely observed by HiRISE in the polar regions. They are widely accepted to result from CO2 gas jet eruptions. Fan lengths, sizes, and shapes can provide information about …
Physical Characterization of 2015 JD1: A Possibly Inhomogeneous Near-Earth Asteroid
Granvik, Mikael; Gustafsson, Annika; Chandler, Colin Orion +7 more
The surfaces of airless bodies such as asteroids are exposed to many phenomena that can alter their physical properties. Bennu, the target of the OSIRIS-REx mission, has demonstrated how complex the surface of a small body can be. In 2019 November, the potentially hazardous asteroid 2015 JD1 experienced a close approach of 0.033 1 au fr…
Spectroscopic Mapping of Io's Surface with HST/STIS: SO2 Frost, Sulfur Allotropes, and Large-scale Compositional Patterns
Brown, Michael E.; Trumbo, Samantha K.; Davis, M. Ryleigh +1 more
Io's intense volcanic activity results in one of the most colorful surfaces in the solar system. Ultraviolet and visible-wavelength observations of Io are critical to uncovering the chemistry behind its volcanic hues. Here, we present global, spatially resolved ultraviolet-visible spectra of Io from the Space Telescope Imaging Spectrograph on the …