Search Publications
Near-infrared Spectroscopy of the Nucleus of Low-activity Comet P/2016 BA14 during Its 2016 Close Approach
Kareta, Theodore; Harris, Walter M.; Reddy, Vishnu +1 more
The near-Earth comet P/2016 BA14 (PanSTARRS) is a slow-rotating, nearly dormant object, a likely dynamical twin of 252P/LINEAR, and was recently shown to have a mid-infrared spectrum very dissimilar to other comets. Comet BA14 was also recently selected as one of the backup targets for the ESA's Comet Interceptor, so a cleare…
Ultraviolet Spectroscopy of Lucy Mission Targets with the Hubble Space Telescope
Emery, Joshua P.; Grundy, Will M.; Humes, Oriel A. +1 more
The recently launched Lucy mission aims to understand the dynamical history of the solar system by examining the Jupiter Trojans, a population of primitive asteroids co-orbital with Jupiter. Using the G280 grism on the Hubble Space Telescope's Wide Field Camera 3, we obtained near-ultraviolet spectra of four of the five Lucy mission targets-(617) …
Identifying Shadowing Signatures of C Ring Ringlets and Plateaus in Cassini Data from Saturn's Ionosphere
Vigren, Erik; Wahlund, Jan-Erik; Dreyer, Joshua +5 more
For orbits 288 and 292 of Cassini's Grand Finale, clear dips (sharp and narrow decreases) are visible in the ${{\rm{H}}}_{2}^{+}$ densities measured by the Ion and Neutral Mass Spectrometer (INMS). In 2017, the southern hemisphere of Saturn was shadowed by its rings and the substructures within. Tracing a path of the solar photons through the ring…
On the Hydrosphere Stability of TESS Targets: Applications to 700 d, 256 b, and 203 b
Kennefick, Julia; Bonney, Paul
A main determinant of the habitability of exoplanets is the presence of stable liquid surface water. In an era of abundant possible targets, the potential to find a habitable world remains a driving force in prioritization. We present here a data-forward method to investigate the likelihood of a stable hydrosphere on the timescales of the formatio…
Seasonal Variations of Chemical Species and Haze in Titan's Upper Atmosphere
Fan, Siteng; Zhao, Daniel; Li, Cheng +3 more
Seasonal variation is significant in Titan's atmosphere owing to the large change of solar insolation resulting from Titan's 26.7° axial tilt relative to the plane of Saturn's orbit. Here we present an investigation of hydrocarbon and nitrile species in Titan's upper atmosphere at 400-1200 km, which includes the mesosphere and the lower thermosphe…
Dione's Thermal Inertia and Bolometric Bond Albedo Derived from Cassini/CIRS Observations of Solar Eclipse Ingress
Spencer, John R.; Howett, Carly J. A.
On 2010 May 18 Cassini's Composite Infrared Spectrometer (CIRS) observed Dione's leading hemisphere as its surface went into solar eclipse. Surface temperatures derived from each of CIRS' focal plane 3 (FP3, 600-1100 cm-1) show a rapid decrease in Dione's surface temperature upon eclipse ingress. This change was compared to the model su…
Refining the Transit-timing and Photometric Analysis of TRAPPIST-1: Masses, Radii, Densities, Dynamics, and Ephemerides
Triaud, Amaury H. M. J.; Foreman-Mackey, Daniel; Meadows, Victoria S. +32 more
We have collected transit times for the TRAPPIST-1 system with the Spitzer Space Telescope over four years. We add to these ground-based, HST, and K2 transit-time measurements, and revisit an N-body dynamical analysis of the seven-planet system using our complete set of times from which we refine the mass ratios of the planets to the star. We next…
Lucy Mission to the Trojan Asteroids: Science Goals
Stern, S. Alan; Noll, Keith S.; Levison, Harold F. +22 more
The Lucy Mission is a NASA Discovery-class mission to send a highly capable and robust spacecraft to investigate seven primitive bodies near both the L4 and L5 Lagrange points with Jupiter: the Jupiter Trojan asteroids. These planetesimals from the outer planetary system have been preserved since early in solar system history…
Ultra-short-period Planets in K2. III. Neighbors are Common with 13 New Multiplanet Systems and 10 Newly Validated Planets in Campaigns 0-8 and 10
Cochran, William D.; Endl, Michael; Howell, Steve B. +14 more
Using the EVEREST photometry pipeline, we have identified 74 candidate ultra-short-period planets (USPs; orbital period P < 1 day) in the first half of the K2 data (Campaigns 0-8 and 10). Of these, 33 candidates have not previously been reported. A systematic search for additional transiting planets found 13 new multiplanet systems containing a…
First Comet Observations with NIRSPEC-2 at Keck: Outgassing Sources of Parent Volatiles and Abundances Based on Alternative Taxonomic Compositional Baselines in 46P/Wirtanen
Villanueva, Geronimo L.; Cochran, Anita L.; Bodewits, Dennis +18 more
A major upgrade to the NIRSPEC instrument at the Keck II telescope was successfully completed in time for near-infrared spectroscopic observations of comet 46P/Wirtanen during its exceptionally close flyby of Earth in 2018 December. These studies determined the abundances of several volatiles, including C2H2, C2H