Search Publications
Lifetimes and Occurrence Rates of Dark Vortices on Neptune from 25 Years of Hubble Space Telescope Images
Wong, Michael H.; Simon, Amy A.; Hsu, Andrew I.
We scoured the full set of blue-wavelength Hubble Space Telescope images of Neptune, finding one additional dark spot in new Hubble data beyond those discovered in 1989, 1994, 1996, and 2015. We report the complete disappearance of the SDS-2015 dark spot, using new Hubble data taken on 2018 September 9-10, as part of the Outer Planet Atmospheres L…
Luminous and Variable Stars in NGC 2403 and M81
Humphreys, Roberta M.; Davidson, Kris; Gordon, Michael S. +2 more
We present the results of spectroscopy and multi-wavelength photometry of luminous and variable star candidates in the nearby spiral galaxies NGC 2403 and M81. We discuss specific classes of stars, the Luminous Blue Variables (LBVs), B[e] supergiants (sgB[e]), and the high-luminosity yellow hypergiants. We identify two new LBV candidates, and thre…
K2-291b: A Rocky Super-Earth in a 2.2 day Orbit
Vanderburg, Andrew; López-Morales, Mercedes; Latham, David W. +43 more
K2-291 is a solar-type star with a radius of R * = 0.899 ± 0.034 R ⊙ and mass of M* = 0.934 ± 0.038 M ⊙. From the K2 C13 data, we found one super-Earth planet (R p = {1.589}-0.072+0.095 R ⊕) transiting this star on a short period orbit (P = {2.225177}-6.…
Phosphorus Abundances in the Hyades and Galactic Disk
Cescutti, G.; Pilachowski, C. A.; Maas, Z. G.
We have measured phosphorus abundances in nine disk stars between -1 < [Fe/H] < -0.5 and in 12 members of the Hyades open cluster using two P I lines at 1.06 µm. High-resolution infrared spectra were obtained using Phoenix on Gemini South and abundances were determined by comparing synthetic spectra to the observations. The average abu…
Qatar Exoplanet Survey: Qatar-8b, 9b, and 10b—A Hot Saturn and Two Hot Jupiters
Bieryla, Allyson; Latham, David W.; Esquerdo, Gilbert A. +26 more
In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey. Qatar-8b is a hot Saturn, with M P = 0.37 M J and R P = 1.3 R J, orbiting a solar-like star every P orb = 3.7 days. Qatar-9b is a hot Jupiter with a mass of M P = 1.2 M J and a radius o…
The Eclipsing δ Scuti Star EPIC 245932119
Kristiansen, Martti H.; Hong, Kyeongsoo; Lee, Jae Woo
We present the physical properties of EPIC 245932119 (K p = +9.82) exhibiting both eclipses and pulsations from the K2 photometry. The binary modeling indicates that the eclipsing system is in detached or semi-detached configurations with a mass ratio of 0.283 or 0.245, respectively, and that its light-curve parameters are almost unaffe…
The HD 181433 Planetary System: Dynamics and a New Orbital Solution
Kane, Stephen R.; Wittenmyer, Robert A.; Horner, Jonathan +7 more
We present a detailed analysis of the orbital stability of the HD 181433 planetary system, finding it to exhibit strong dynamical instability across a wide range of orbital eccentricities, semimajor axes, and mutual inclinations. We also analyze the behavior of an alternative system architecture, proposed by Campanella, and find that it offers gre…
Asteroseismology of the Multiplanet System K2-93
Vanderburg, Andrew; Chaplin, William J.; Davies, Guy R. +14 more
We revisit the analysis of the bright multiplanet system K2-93, discovered with data taken by the K2 mission. This system contains five identified planets ranging in size from sub-Neptune to Jupiter size. The K2 data available at the discovery of the system only showed single transits for the three outer planets, which allowed weak constraints to …
APOGEE/Kepler Overlap Yields Orbital Solutions for a Variety of Eclipsing Binaries
Stassun, Keivan G.; Agol, Eric; Rawls, Meredith L. +4 more
Spectroscopic eclipsing binaries (SEBs) are fundamental benchmarks in stellar astrophysics and today are observed in breathtaking detail by missions like the Transiting Exoplanet Survey Satellite (TESS), Kepler, and Apache Point Observatory Galactic Evolution Experiment (APOGEE). We develop a methodology for simultaneous analysis of high-precision…
OGLE-2015-BLG-1670Lb: A Cold Neptune beyond the Snow Line in the Provisional WFIRST Microlensing Survey Field
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +56 more
We present the analysis of the microlensing event OGLE-2015-BLG-1670, detected in a high-extinction field very close to the Galactic plane. Due to the dust extinction along the line of sight, this event was too faint to be detected before it reached the peak of magnification. The microlensing light-curve models indicate a high-magnification event …