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The HST PanCET Program: Hints of Na I and Evidence of a Cloudy Atmosphere for the Inflated Hot Jupiter WASP-52b
DOI: 10.3847/1538-3881/aaee89 Bibcode: 2018AJ....156..298A

Nikolov, Nikolay; Sing, David K.; Stevenson, Kevin B. +16 more

We present an optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from the Space Telescope Imaging Spectrograph mounted on the Hubble Space Telescope, combined with Spitzer/Infrared Array Camera photometry at 3.6 and 4.5 µm. Since WASP-52 is a moderately active (log(L x

2018 The Astronomical Journal
Gaia eHST 40
An HST/STIS Optical Transmission Spectrum of Warm Neptune GJ 436b
DOI: 10.3847/1538-3881/aaa008 Bibcode: 2018AJ....155...66L

Knutson, Heather; McCullough, Peter; Lothringer, Joshua D. +9 more

GJ 436b is a prime target for understanding warm Neptune exoplanet atmospheres and a target for multiple James Webb Space Telescope (JWST) Guaranteed Time Observation programs. Here, we report the first space-based optical transmission spectrum of the planet using two Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) transit…

2018 The Astronomical Journal
eHST 40
High-precision Orbit Fitting and Uncertainty Analysis of (486958) 2014 MU69
DOI: 10.3847/1538-3881/aac2e1 Bibcode: 2018AJ....156...20P

Tanga, Paolo; Stern, S. Alan; Kavelaars, J. J. +11 more

NASA’s New Horizons spacecraft will conduct a close flyby of the cold-classical Kuiper Belt Object (KBO) designated (486958) 2014 MU69 on 2019 January 1. At a heliocentric distance of 44 au, “MU69” will be the most distant object ever visited by a spacecraft. To enable this flyby, we have developed an extremely high-precision orbit fitting and unc…

2018 The Astronomical Journal
Gaia eHST 39
The 0.8-4.5 µm Broadband Transmission Spectra of TRAPPIST-1 Planets
DOI: 10.3847/1538-3881/aade94 Bibcode: 2018AJ....156..218D

Queloz, D.; Agol, E.; Delrez, L. +18 more

The TRAPPIST-1 planetary system provides an exceptional opportunity for the atmospheric characterization of temperate terrestrial exoplanets with the upcoming James Webb Space Telescope (JWST). Assessing the potential impact of stellar contamination on the planets’ transit transmission spectra is an essential precursor to this characterization. Pl…

2018 The Astronomical Journal
eHST 39
K2-231 b: A Sub-Neptune Exoplanet Transiting a Solar Twin in Ruprecht 147
DOI: 10.3847/1538-3881/aab49c Bibcode: 2018AJ....155..173C

Torres, Guillermo; Vanderburg, Andrew; Huber, Daniel +9 more

We identify a sub-Neptune exoplanet (R p = 2.5 ± 0.2 {R}\oplus ) transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H] = +0.1 dex). The ∼81 day light curve for EPIC 219800881 (V = 12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ∼0.06%, and a duration of ∼4 hr. B…

2018 The Astronomical Journal
Gaia 38
Pre-discovery Observations and Orbit of Comet C/2017 K2 (PANSTARRS)
DOI: 10.3847/1538-3881/aa9be1 Bibcode: 2018AJ....155...25H

Jewitt, David; Clark, David; Hui, Man-To

We present a study of comet C/2017 K2 (PANSTARRS) using pre-discovery archival data taken from 2013 to 2017. Our measurements show that the comet has been marginally increasing in activity since at least 2013 May (heliocentric distance of {r}{{H}}=23.7 {au} pre-perihelion). We estimate the mass-loss rate during the period 2013-2017 as \…

2018 The Astronomical Journal
eHST 38
Historical and Contemporary Trends in the Size, Drift, and Color of Jupiter's Great Red Spot
DOI: 10.3847/1538-3881/aaae01 Bibcode: 2018AJ....155..151S

Wong, Michael H.; Orton, Glenn S.; Simon, Amy A. +3 more

Observations of Jupiter’s Great Red Spot (GRS) span more than 150 years. This allows for careful measurements of its size and drift rate. High spatial resolution spacecraft data also allow tracking of its spectral characteristics and internal dynamics and structure. The GRS continues to shrink in longitudinal length at an approximately linear rate…

2018 The Astronomical Journal
eHST 37
Speckle Interferometry at SOAR in 2016 and 2017
DOI: 10.3847/1538-3881/aabf8d Bibcode: 2018AJ....155..235T

Tokovinin, Andrei; Horch, Elliott P.; Mason, Brian D. +2 more

The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2016 and 2017 are given, totaling 2483 measurements of 1570 resolved pairs and 609 non-resolutions. We describe briefly recent changes in the instrument and observing method and quantify the accuracy of the pixel scale and position angle c…

2018 The Astronomical Journal
Gaia Hipparcos 37
Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810
DOI: 10.3847/1538-3881/aae1f5 Bibcode: 2018AJ....156..213M

Howard, Andrew W.; Fischer, Debra A.; Ment, Kristo +2 more

The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce t…

2018 The Astronomical Journal
Gaia 37
Community Targets of JWST’s Early Release Science Program: Evaluation of WASP-63b
DOI: 10.3847/1538-3881/aacea7 Bibcode: 2018AJ....156..103K

Deming, Drake; Madhusudhan, Nikku; Burrows, Adam +21 more

We present observations of WASP-63b by the Hubble Space Telescope (HST) as part of “A Preparatory Program to Identify the Single Best Transiting Exoplanet for James Webb Space Telescope (JWST) Early Release Science (ERS).” WASP-63b is one of the community targets under consideration for the JWST ERS program. We present a spectrum derived from a si…

2018 The Astronomical Journal
eHST 36