Search Publications
The New Horizons and Hubble Space Telescope search for rings, dust, and debris in the Pluto-Charon system
Hamilton, Douglas P.; Olkin, Cathy B.; Stern, S. Alan +11 more
We conducted an extensive search for dust or debris rings in the Pluto-Charon system before, during, and after the New Horizons encounter in July 2015. Methodologies included attempting to detect features by back-scattered light during the approach to Pluto (phase angle α ∼ 15°), in situ detection of impacting particles, a search for stellar occul…
Iron distribution of the Moon observed by the Kaguya gamma-ray spectrometer: Geological implications for the South Pole-Aitken basin, the Orientale basin, and the Tycho crater
Wöhler, C.; Ohtake, M.; Berezhnoy, A. A. +5 more
In this study we describe the distribution of iron on the Moon as obtained by the Kaguya high energy resolution gamma-ray spectrometer (KGRS). We achieved for the first time the identification of iron based on the fast neutron flux obtained by the KGRS. The iron distribution obtained by KGRS is compared to that of the Lunar Prospector Gamma-Ray Sp…
Is Kasei Valles (Mars) the largest volcanic channel in the solar system?
Leverington, David W.
With a length of more than 2000 km and widths of up to several hundred kilometers, Kasei Valles is the largest outflow system on Mars. Superficially, the scabland-like character of Kasei Valles is evocative of terrestrial systems carved by catastrophic aqueous floods, and the system is widely interpreted as a product of outbursts from aquifers. Ho…
Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)
Hudson, Reggie L.; Loeffler, Mark J.
Here we present our recent studies on the color and spectral reflectance changes induced by ∼0.9 MeV proton irradiation of ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. Ultraviolet-visible spectroscopy was used to observe and identify reaction produ…
On the icy edge at Louth and Korolev craters
Bapst, Jonathan; Byrne, Shane; Brown, Adrian J.
The modern climate of Mars has been well characterized from over a decade of orbiting spacecraft, in situ measurements via landers/rovers, and theoretical advances in climate modeling. Nonetheless, important questions remain unanswered, including the present-day mass balance of the north polar residual cap and its icy outliers. Exposed water-ice m…
Composition and structure of fresh ammonia clouds on Jupiter based on quantitative analysis of Galileo/NIMS and New Horizons/LEISA spectra
Sromovsky, L. A.; Fry, P. M.
Ammonia gas has long been assumed to be the main source of condensables for the upper cloud layer on Jupiter, but distinctive spectral features associated with ammonia have been seen only rarely. Since both ammonia and NH4SH absorb in the 3 µm region, and widespread absorption in the 3 µm region was present (Sromovsky and Fr…
Stepped fans and facies-equivalent phyllosilicates in Coprates Catena, Mars
Warner, N. H.; Gupta, S.; Grindrod, P. M. +2 more
Stepped fan deposits and phyllosilicate mineralogies are relatively common features on Mars but have not previously been found in association with each other. Both of these features are widely accepted to be the result of aqueous processes, but the assumed role and nature of any water varies. In this study we have investigated two stepped fan depo…
Constraining the parameter space of comet simulation experiments
Hagermann, Axel; Kaufmann, Erika
Our interpretation of the data returned by Rosetta and other cometary missions is based on the predictions of theoretical models and the results of laboratory experiments. For example, Kossacki et al. (2015) showed that 67P's surface hardness reported by Spohn et al. (2015) can be explained by sintering. The present work supports Rosetta's observa…
The upcoming mutual event season for the Patroclus-Menoetius Trojan binary
Buie, M. W.; Grundy, W. M.; Noll, K. S. +1 more
We present new Hubble Space Telescope and ground-based Keck observations and new Keplerian orbit solutions for the mutual orbit of binary Jupiter Trojan asteroid (617) Patroclus and Menoetius, targets of NASA's Lucy mission. We predict event times for the upcoming mutual event season, which is anticipated to run from late 2017 through mid 2019.
Regional stratigraphy of the south polar layered deposits (Promethei Lingula, Mars): "Discontinuity-bounded" units in images and radargrams
Thomas, Nicolas; Forget, François; Rossi, Angelo Pio +5 more
The Mars South Polar Layered Deposits (SPLD) are the result of depositional and erosional events, which are marked by different stratigraphic sequences and erosional surfaces. To unambiguously define the stratigraphic units at regional scale, we mapped the SPLD on the basis of observed discontinuities (i.e., unconformities, correlative discontinui…