Search Publications

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…

Comet 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova, and 46P/Wirtanen: Water Production Activity over 21 yr with SOHO/SWAN

Bertaux, J. -L.; Combi, M. R.; Quémerais, E. +3 more

In 2017, 2018, and 2019, comets 46P/Wirtanen, 45P/Honda-Mrkos-Pajdusakova, and 41P/Tuttle-Giacobini-Kresak all had perihelion passages. Their hydrogen comae were observed by the Solar Wind ANisotropies (SWAN) all-sky hydrogen Lyα camera on the SOlar and Heliospheric Observer (SOHO) satellite: comet 46P for the fourth time and comets 45P and 41P fo…

Experimental Investigation of Oxidation of Pyroxene and Basalt: Implications for Spectroscopic Analyses of the Surface of Venus and the Ages of Lava Flows

Filiberto, J.; Cutler, K. S.; Treiman, A. H. +1 more

Alteration of basalt on the surface of Venus should be dominated by nanophase hematite and sulfate coatings, but the timescale of oxidation and how that affects spectroscopic measurements has not been extensively studied. The oxidation rate and the effect on reflectance spectroscopy are needed to constrain the age of lava flows with high emissivit…

Stellar Occultation by the Resonant Trans-Neptunian Object (523764) 2014 WC510 Reveals a Close Binary TNO

Buie, Marc W.; Wasserman, Lawrence H.; Leiva, Rodrigo +22 more

We report on the stellar occultation by (523764) 2014 WC₅₁₀ observed on 2018 December 1 UT. This occultation campaign was part of the Research and Education Collaborative Occultation Network (RECON), a network of small telescopes spread over 2000 km in western USA and Canada. Light curves from six stations revealed three groups of two o…

Detection of a Satellite of the Trojan Asteroid (3548) Eurybates—A Lucy Mission Target

Marchi, S.; Weaver, H. A.; Buie, M. W. +8 more

We describe the discovery of a satellite of the Trojan asteroid (3548) Eurybates in images obtained with the Hubble Space Telescope. The satellite was detected on three separate epochs, two in 2018 September and one in 2020 January. The satellite has a brightness in all three epochs consistent with an effective diameter of d₂ = 1.2 ± 0.…

Possible Evidence of p-modes in Cassini Measurements of Saturn's Gravity Field

Iess, Luciano; Durante, Daniele; Markham, Steve +1 more

We analyze the range-rate residual data from Cassini's gravity experiment that cannot be explained with a static, zonally symmetric gravity field. We reproduce the data using a simple forward model of gravity perturbations from normal modes. To do this, we stack data from multiple flybys to improve sensitivity. We find a partially degenerate set o…

Saturn's Atmospheric Helium Abundance from Cassini Composite Infrared Spectrometer Data

Achterberg, Richard K.; Flasar, F. Michael

We use thermal infrared data from the Composite Infrared Spectrometer, which was on board the Cassini orbiter, to retrieve the helium abundance in Saturn's visible atmosphere. We find that the data is most consistent with a helium-to-hydrogen mole ratio in the range between 0.04 and 0.075, near the lower end of previous measurements, and implying …