Search Publications
The Radial Velocity Variability of the K-giant γ Draconis: Stellar Variability Masquerading as a Planet
Dreizler, S.; Hatzes, A. P.; Cochran, W. D. +9 more
We present precise stellar radial velocity (RV) measurements of γ Dra taken from 2003 to 2017. The data from 2003 to 2011 show coherent, long-lived variations with a period of 702 days. These variations are consistent with the presence of a planetary companion having m sin i = 10.7 M Jup whose orbital properties are typical for giant pl…
Spectroscopic Validation of Low-metallicity Stars from RAVE
Whitten, Devin D.; Beers, Timothy C.; Lee, Young Sun +16 more
We present results from a medium-resolution (R ∼ 2000) spectroscopic follow-up campaign of 1694 bright (V < 13.5), very metal-poor star candidates from the RAdial Velocity Experiment (RAVE). Initial selection of the low-metallicity targets was based on the stellar parameters published in RAVE Data Releases 4 and 5. Follow up was accomplished wi…
The HST PanCET Program: Hints of Na I and Evidence of a Cloudy Atmosphere for the Inflated Hot Jupiter WASP-52b
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
An HST/STIS Optical Transmission Spectrum of Warm Neptune GJ 436b
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…
High-precision Orbit Fitting and Uncertainty Analysis of (486958) 2014 MU69
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…
The 0.8-4.5 µm Broadband Transmission Spectra of TRAPPIST-1 Planets
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…
K2-231 b: A Sub-Neptune Exoplanet Transiting a Solar Twin in Ruprecht 147
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…
Pre-discovery Observations and Orbit of Comet C/2017 K2 (PANSTARRS)
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 \…
Historical and Contemporary Trends in the Size, Drift, and Color of Jupiter's Great Red Spot
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…
Speckle Interferometry at SOAR in 2016 and 2017
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…