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Kepler-1656b: A Dense Sub-Saturn with an Extreme Eccentricity
Knutson, Heather A.; Fulton, Benjamin J.; Hirsch, Lea A. +6 more
Kepler-1656b is a 5 {R}\oplus planet with an orbital period of 32 days initially detected by the prime Kepler mission. We obtained precision radial velocities of Kepler-1656 with Keck/HIRES in order to confirm the planet and to characterize its mass and orbital eccentricity. With a mass of 48 ± 4 {M}\oplus , Kepler-1656b is …
Spectroscopic Orbits of Subsystems in Multiple Stars. III.
Tokovinin, Andrei
Spectroscopic orbits are computed for inner pairs in six nearby hierarchical multiple systems (HIP 35733, 95106/95110, 105441, 105585/105569, 105947, and 109951). Radial velocities and resolved measurements, when available, are used to derive combined sets of outer orbital elements for three systems. Each multiple system is discussed individually.…
Hubble Space Telescope Observations of 3200 Phaethon at Closest Approach
Mutchler, Max; Jewitt, David; Agarwal, Jessica +1 more
We present Hubble Space Telescope observations of the active asteroid (and Geminid stream parent) 3200 Phaethon when at its closest approach to Earth (separation 0.07 au) in 2017 December. Images were recorded within ∼1° of the orbital plane, providing extra sensitivity to low surface brightness caused by scattering from a large-particle trail. We…
FUV Spectral Signatures of Molecules and the Evolution of the Gaseous Coma of Comet 67P/Churyumov-Gerasimenko
Parker, Joel Wm.; Bertaux, Jean-Loup; Stern, S. Alan +10 more
The Alice far-ultraviolet imaging spectrograph onboard Rosetta observed emissions from atomic and molecular species from within the coma of comet 67P/Churyumov-Gerasimenko during the entire escort phase of the mission from 2014 August to 2016 September. The initial observations showed that emissions of atomic hydrogen and oxygen close to the surfa…
ALICE Data Release: A Revaluation of HST-NICMOS Coronagraphic Images
Vigan, Arthur; Choquet, Élodie; Soummer, Rémi +1 more
The Hubble Space Telescope NICMOS instrument was used from 1997 to 2008 to perform coronagraphic observations of about 400 targets. Most of them were part of surveys looking for substellar companions or resolved circumstellar disks to young nearby stars, making the NICMOS coronagraphic archive a valuable database for exoplanets and disks studies. …
Jupiter’s Mesoscale Waves Observed at 5 µm by Ground-based Observations and Juno JIRAM
Fletcher, Leigh N.; Kraaikamp, E.; Hueso, R. +12 more
We characterize the origin and evolution of a mesoscale wave pattern in Jupiter’s North Equatorial Belt (NEB), detected for the first time at 5 µm using a 2016-17 campaign of “lucky imaging” from the VISIR instrument on the Very Large Telescope and the NIRI instrument on the Gemini observatory, coupled with M-band imaging from Juno’s JIRAM i…
The Enigmatic (Almost) Dark Galaxy Coma P: The Atomic Interstellar Medium
McQuinn, Kristen B. W.; Cannon, John M.; Salzer, John J. +12 more
We present new high-resolution H I spectral line imaging of Coma P, the brightest H I source in the system HI 1232+20. This galaxy with extremely low surface brightness was first identified in the ALFALFA survey as an “(Almost) Dark” object: a clearly extragalactic H I source with no obvious optical counterpart in existing optical survey data (alt…
The Young Massive Star Cluster Westerlund 2 Observed with MUSE. I. First Results on the Cluster Internal Motion from Stellar Radial Velocities
Grebel, Eva K.; Kamann, Sebastian; McLeod, Anna Faye +7 more
Westerlund 2 (Wd2) is the central ionizing star cluster of the H II region RCW 49 and the second most massive young star cluster ({\text{}}M=(3.6+/- 0.3)× {10}4 {\text{}}{M}⊙ ) in the Milky Way. Its young age (∼2 Myr) and close proximity to the Sun (∼4 kpc) makes it a perfect target to study stars emerging from their parental…
Bi-lobed Shape of Comet 67P from a Collapsed Binary
Nesvorný, David; Vokrouhlický, David; Parker, Joel
The Rosetta spacecraft observations revealed that the nucleus of comet 67P/Churyumov-Gerasimenko consists of two similarly sized lobes connected by a narrow neck. Here, we evaluate the possibility that 67P is a collapsed binary. We assume that the progenitor of 67P was a binary and consider various physical mechanisms that could have brought the b…
Probing Oort Clouds around Milky Way Stars with CMB Surveys
Jain, Bhuvnesh; Blake, Cullen H.; Baxter, Eric J.
Long-period comets observed in our solar system are believed to originate from the Oort cloud, which is estimated to extend from roughly a few thousand to 105 au from the Sun. Despite many theoretical arguments for the existence of the Oort cloud, no direct observations of outer Oort cloud objects have been reported. Here, we explore th…