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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…
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
Vertical Structure and Color of Jovian Latitudinal Cloud Bands during the Juno Era
Baines, Kevin H.; Irwin, Patrick G. J.; Dahl, Emma K. +6 more
The identity of the coloring agent(s) in Jupiter's atmosphere and the exact structure of Jupiter's uppermost cloud deck are yet to be conclusively understood. The Crème Brûlée model of Jupiter's tropospheric clouds, originally proposed by Baines et al. and expanded upon by Sromovsky et al. and Baines et al., presumes that the chromophore measured …
Narrowband Observations of Comet 46P/Wirtanen during Its Exceptional Apparition of 2018/19. I. Apparent Rotation Period and Outbursts
Skiff, Brian A.; Feaga, Lori M.; Schleicher, David G. +4 more
We obtained broad- and narrowband images of the hyperactive comet 46P/Wirtanen on 33 nights during its 2018/2019 apparition, when the comet made a historic close approach to the Earth. With our extensive coverage, we investigated the temporal behavior of the comet on both seasonal and rotational timescales. We used CN observations to explore the c…
Six Outbursts of Comet 46P/Wirtanen
Duev, Dmitry A.; Southworth, J.; Bellm, Eric C. +33 more
Cometary activity is a manifestation of sublimation-driven processes at the surface of nuclei. However, cometary outbursts may arise from other processes that are not necessarily driven by volatiles. In order to fully understand nuclear surfaces and their evolution, we must identify the causes of cometary outbursts. In that context, we present a s…
The Orbit and Density of the Jupiter Trojan Satellite System Eurybates-Queta
Buie, Marc W.; Noll, Keith S.; Levison, Harold F. +8 more
We report observations of the Jupiter Trojan asteroid (3548) Eurybates and its satellite Queta with the Hubble Space Telescope and use these observations to perform an orbital fit to the system. Queta orbits Eurybates with a semimajor axis of 2350 ± 11 km at a period of 82.46 ± 0.06 days and an eccentricity of 0.125 ± 0.009. From this orbit we der…
Transmission Spectroscopy of the Earth-Sun System to Inform the Search for Extrasolar Life
May, E. M.; Mayorga, L. C.; Sotzen, Kristin S. +7 more
Upcoming NASA astrophysics missions such as the James Webb Space Telescope will search for signs of life on planets transiting nearby stars. Doing so will require coadding dozens of transmission spectra to build up sufficient signal to noise while simultaneously accounting for challenging systematic effects such as surface/weather variability, atm…
FUV Observations of the Inner Coma of 46P/Wirtanen
Parker, Joel Wm.; Harris, Walter M.; Bodewits, Dennis +6 more
Far-ultraviolet observations of comets yield information about the energetic processes that dissociate the sublimated gases from their primitive surfaces. Understanding which emission processes are dominant, their effects on the observed cometary spectrum, and how to properly invert the spectrum back to the composition of the presumably pristine s…
The Geographic Distribution of Dense-phase O2 on Ganymede
Brown, Michael E.; Trumbo, Samantha K.; Adams, Danica
Ground-based spectroscopy of Ganymede's surface has revealed the surprising presence of dense-phase molecular oxygen (O2) via weak absorptions at visible wavelengths. To date, the state and stability of this O2 at the temperatures and pressures of Ganymede's surface are not understood. Its spatial distribution in relation to …