Search Publications
Variations in the Ionospheric Peak Altitude at Mars in Response to Dust Storms: 13 Years of Observations From the Mars Express Radar Sounder
Gurnett, D. A.; Němec, F.; Morgan, D. D. +7 more
Previous observations have shown that, during Martian dust storms, the peak of the ionosphere rises in altitude. Observational studies of this type, however, have been extremely limited. Using 13 years of ionospheric peak altitude data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument on Mars Express, we study how the …
Aram Dorsum: An Extensive Mid-Noachian Age Fluvial Depositional System in Arabia Terra, Mars
Sefton-Nash, Elliot; Williams, Rebecca M. E.; Fawdon, Peter +5 more
A major debate in Mars science is the nature of the early Mars climate, and the availability of precipitation and runoff. Observations of relict erosional valley networks have been proposed as evidence for extensive surface runoff around the Noachian-Hesperian boundary. However, these valley networks only provide a time-integrated record of landsc…
Magnetic Properties of Asteroid (162173) Ryugu
Motschmann, Uwe; Fujimoto, Masaki; Richter, Ingo +22 more
Observations of the magnetization state of asteroids indicate diverse properties. Values between 1.9 × 10-6 Am2/kg (Eros) and 10-2 Am2/kg (Braille) have been reported. A more detailed understanding of asteroidal magnetic properties allows far-reaching conclusions of the magnetization mechanism as well as…
The Bathymetry of Moray Sinus at Titan's Kraken Mare
Lunine, J. I.; Hayes, A. G.; Le Gall, A. +4 more
Moray Sinus is an estuary located at the northern end of Titan's Kraken Mare. The Cassini RADAR altimeter acquired three segments over this mare during the T104 flyby of Titan, on August 21, 2014. Herein, we present a detailed analysis of the received echoes. Some of these waveforms exhibit a reflection from the seafloor, from up to 85-18+28 m of …
Polyphase Mid-Latitude Glaciation on Mars: Chronology of the Formation of Superposed Glacier-Like Forms from Crater-Count Dating
Hepburn, A. J.; Hubbard, B.; Ng, F. S. L. +2 more
Reconstructing Mars's glacial history informs understanding of its physical environment and past climate. The known distribution of viscous flow features (VFFs) containing water ice suggests that its mid-latitudes were glaciated during the Late Amazonian period (the last several hundred million years). The identification of a subgroup of VFFs—call…
Ganymede's Far-Ultraviolet Reflectance: Constraining Impurities in the Surface Ice
Nichols, J. D.; Raut, U.; Retherford, K. D. +2 more
We present reflectance spectra of Ganymede's leading and trailing hemispheres in the wavelength range 138-215 nm, obtained by the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) in 2014. The most notable feature of both spectra is the absence of a sharp water absorption edge at ~165 nm, seen in laboratory measurements of ice reflectiv…
Paleolakes in the Northwest Hellas Region, Mars: Implications for the Regional Geologic History and Paleoclimate
Xiao, Long; Glotch, Timothy D.; Zhao, Jiannan
Hellas basin is one of the largest and oldest impact basins on the Martian surface. Its surrounding highland regions have undergone complicated geologic processes after the formation of Hellas basin. However, the geologic and climatic histories of the highlands surrounding Hellas are still unclear. Paleolakes provide us clues to answer these quest…
Small Impact Crater Populations on Saturn's Moon Tethys and Implications for Source Impactors in the System
Ferguson, S. N.; Rhoden, A. R.; Kirchoff, M. R.
Current estimates place the ages of the inner Saturnian satellites (Mimas, Enceladus, Tethys, Dione, and Rhea) between 4.5 Gyr and 100 Myr. These estimates are based on impact crater measurements and dynamical simulations, both of which have uncertainties. Models of satellite evolution are inherently simplified and rely on uncertain or unknown par…
A Survey of Small-Scale Waves and Wave-Like Phenomena in Jupiter's Atmosphere Detected by JunoCam
Wong, Michael H.; Fletcher, Leigh N.; Ingersoll, Andrew P. +17 more
In the first 20 orbits of the Juno spacecraft around Jupiter, we have identified a variety of wave-like features in images made by its public-outreach camera, JunoCam. Because of Juno's unprecedented and repeated proximity to Jupiter's cloud tops during its close approaches, JunoCam has detected more wave structures than any previous surveys. Most…
Studies of the 2018/Mars Year 34 Planet-Encircling Dust Storm
Guzewich, S. D.; Fedorova, A. A.; Kahre, M. A. +1 more
Mars' planet-encircling or global dust storms (GDSs) are an iconic and enigmatic feature of the Red Planet. Occurring every few Mars Years (MYs), on average, they are a stochastic process in the otherwise largely repeatable annual cycle of martian weather. In 2018 (MY 34 in the calendar of Clancy et al. [2000],