Search Publications

Variable X-Ray Emission of Comet 46P/Wirtanen

Bodewits, Dennis; Christian, Damian J.; Koutroumpa, Dimitra +3 more

In this paper, we present an analysis of X-ray and optical/ultraviolet (UV) data from the favorable (Δ ~ 0.077 au) 2018 apparition of comet 46P/Wirtanen. The comet was observed during three different epochs (before, during, and after perihelion) over a 1.5 month period using the X-Ray Telescope (XRT) and Ultraviolet and Optical Telescope (UVOT) in…

Exploring Ceres's Unusual Regolith Porosity and Its Implications for Volatile Retention

Heggy, Essam; Palmer, Elizabeth M.; Letertre, Thibaut +1 more

Asteroid Ceres, the only dwarf planet located in the inner solar system, shows unique surface mineralogy and geomorphology as observed by the Dawn mission. Of particular interest is understanding the role that upper regolith porosity plays in retaining volatiles and shaping Ceres' surface. Unfortunately, Ceres' near-surface porosity remains largel…

No Evidence for Time Variation in Saturn's Internal Magnetic Field

Cao, Hao; Bloxham, Jeremy; Moore, Kimberly M. +2 more

The time variation of a planetary magnetic field can reveal important aspects of a planet's interior structure. Searching for time variation in planetary magnetic fields other than Earth has proved challenging owing to the small number of spacecraft missions flown to date, but such a detection may be possible given a sufficiently long baseline for…

The Dark Side of Pluto

White, Oliver L.; Bertrand, Tanguy; McKinnon, William B. +10 more

During its departure from Pluto, New Horizons used its LORRI camera to image a portion of Pluto's southern hemisphere that was in a decades-long seasonal winter darkness, but still very faintly illuminated by sunlight reflected by Charon. Recovery of this faint signal was technically challenging. The bright ring of sunlight forward-scattered by ha…

Constraints on Sub-Neptune Planet Candidate KOI-972.01 via Joint Variability/Gravity-darkening Analysis

Barnes, Jason W.; Myers, Samuel A.; Ahlers, John P.

We analyze Kepler photometry of transiting planet candidate KOI-972.01, accounting for both stellar variability and gravity darkening. KOI-972.01 stands out because of its small radius, less than that of Neptune, and because of its intermediate orbit period at 13.12 days, long enough to avoid significant tidal evolution, and thus it represents an …

On Charon's Far-ultraviolet Surface Reflectance

Parker, Joel Wm.; Stern, S. Alan; Verbiscer, Anne J. +3 more

We present the first measurements of Charon's far-ultraviolet (FUV) surface reflectance, obtained by the Alice spectrograph on New Horizons. We find no measurable flux shortward of 1650 Å, and Charon's geometric albedo is <0.019 (3σ) at 1600 Å. From 1650 to 1725 Å, Charon's geometric albedo increases to 0.166 ± 0.068 and remains nearly constant…

Erratum: "Changes in a Dusty Ringlet in the Cassini Division after 2010" (2020, PSJ, 1, 43)

Bridges, Bill; Hedman, Matthew

Titan's "Average" Ionospheric Structures from Cassini

Ip, Wing-Huen; Hsu, Jen-Kai

The decadal observations of Titan's neutral atmosphere and ionosphere by the Ion and Neutral Mass Spectrometer mass spectrometer and other instruments on board the Cassini spacecraft at the Saturnian system provide a precious data set concerning the large-scale structure of Titan's upper ionosphere. An attempt is made in this study to generate ave…