Search Publications
C-Complex Asteroids: UV-Visible Spectral Characteristics and Implications for Space Weathering Effects
Vilas, Faith; Hendrix, Amanda R.
Space weathering effects on the rocky S-class asteroids are well understood. However, on the low-albedo C-complex asteroids, such as spacecraft targets Bennu and Ryugu, the situation is more complicated, especially due to a lack of spectral features throughout the visible-near infrared spectral region. Here we show, through a combination of observ…
Global Distribution of the Solar Wind Flux and Velocity From SOHO/SWAN During SC-23 and SC-24
Schmidt, W.; Quémerais, E.; Koutroumpa, D. +1 more
We analyze SOHO (SOlar Heliospheric Observatory)/SWAN (Solar Wind ANisotropy) hydrogen Lyman-α data collected between 1996 and 2018 to derive the solar wind latitudinal distribution over time. Full-sky interplanetary Lyman-α maps are inverted to derive the total hydrogen ionization rate latitude profiles, normalized to proton charge-exchange and p…
Jovian Auroral Radio Sources Detected In Situ by Juno/Waves: Comparisons With Model Auroral Ovals and Simultaneous HST FUV Images
Kurth, W. S.; Lamy, L.; Zarka, P. +4 more
Since the discovery of Jovian auroral radio emissions, the question arises of the source positions of the different components (broadband kilometric, hectometric, and decametric) and their association with far ultraviolet (FUV) auroral emissions. We surveyed Juno's first 15 perijoves to track local radio sources from in situ Juno/Waves measurement…
Raised Rims Around Titan's Sharp-Edged Depressions
Lunine, J. I.; Hayes, A. G.; Lopes, R. M. C. +6 more
We perform a systematic survey of Titan's sharp-edged depressions (SEDs) using a combination of Cassini synthetic aperture radar images and delay-Doppler processed altimetry. We identify a characteristic bright-dark pattern around 172 SEDs that correlates with elevated features only resolved with the highest resolution topographic data. We find th…
Formation of a New Great Dark Spot on Neptune in 2018
Simon, A. A.; Wong, M. H.; Hsu, A. I.
For the first time, Hubble Space Telescope visible-wavelength imaging shows the formation history of a dark vortex on Neptune. A new northern Great Dark Spot (NDS-2018) was discovered in September and November 2018 images, spanning roughly 12° of latitude and 27° in longitude (11,000 × 5,000 km) at 23°N planetographic latitude. NDS-2018 is similar…
High-Frequency Wave Generation in Magnetotail Reconnection: Nonlinear Harmonics of Upper Hybrid Waves
Graham, Daniel B.; Yoon, Peter H.; Sibeck, David G. +4 more
MMS3 spacecraft passed the vicinity of the electron diffusion region of magnetotail reconnection on 3 July 2017, observing discrepancies between perpendicular electron bulk velocities and E>→×B>→ drift, and agyrotropic electron crescent distributions. Analyzing linear wave dispersions, Burch et al. (2019,
The Effects of Crustal Magnetic Fields and Solar EUV Flux on Ionopause Formation at Mars
Gurnett, D. A.; Morgan, D. D.; Kopf, A. J. +5 more
We study the ionopause of Mars using a database of 6,893 ionopause detections obtained over 11 years by the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment. The ionopause, in this work, is defined as a steep density gradient that appears in MARSIS remote sounding ionograms as a horizontal line at frequencies below 0.…
Observational Evidence for Summer Rainfall at Titan's North Pole
Sotin, Christophe; Barnes, Jason W.; Soderblom, Jason M. +13 more
Methane rain on Saturn's moon Titan makes it the only place, other than Earth, where rain interacts with the surface. When and where that rain wets the surface changes seasonally in ways that remain poorly understood. Here we report the discovery of a bright ephemeral feature covering an area of 120,000 km2 near Titan's north pole in ob…
The 2018 Martian Global Dust Storm Over the South Polar Region Studied With MEx/VMC
Hueso, R.; Sánchez-Lavega, A.; Titov, D. +6 more
We study the 2018 Martian global dust storm (GDS 2018) over the Southern Polar Region using images obtained by the Visual Monitoring Camera (VMC) on board Mars Express (MEx) during June and July 2018. Dust penetrated into the polar cap region but never covered the cap completely, and its spatial distribution was nonhomogeneous and rapidly changing…
Jovian High-Latitude Ionospheric Ions: Juno In Situ Observations
Thomsen, M. F.; Wilson, R. J.; Louarn, P. +10 more
The low-altitude, high-velocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the first in situ observations of the high-latitude ionospheric plasma. Ions are observed to energies below 1 eV. The high-latitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, s…