Search Publications
A Fast Approximate Approach to Microlensing Survey Analysis
Pepper, Joshua; Khakpash, Somayeh; Penny, Matthew
Microlensing can be used to discover exoplanets of a wide range of masses with orbits beyond ∼1 au, and even free-floating planets. The Wide Field Infrared Survey Telescope (WFIRST) mission will use microlensing to discover approximately 1600 planets by monitoring ∼100 million stars to find ∼50,000 microlensing events. Modeling each microlensing e…
Spectroscopic Redshift of the Gamma-Ray Blazar B2 1215+30 from Lyα Emission
Furniss, A.; Johnson, C. A.; Williams, D. A. +4 more
We report on Cosmic Origin Spectrograph observations of the gamma-ray bright blazar B2 1215+30, collected in 2015 November. These observations allow for the confirmation of the source redshift from the detection of a Lyα emission feature at λ ∼ 1374 Å. The emission feature places the source at a redshift of z = 0.1305 ± 0.003, confirming the sourc…
He II Emission from Wolf-Rayet Stars as a Tool for Measuring Dust Reddening
Leitherer, Claus; Faisst, Andreas; Lee, Janice C.
We calibrated a technique to measure dust attenuation in star-forming galaxies. The technique utilizes the stellar-wind lines in Wolf-Rayet stars, which are widely observed in galaxy spectra. The He II 1640 and 4686 features are recombination lines whose ratio is largely determined by atomic physics. Therefore they can serve as a stellar dust prob…
Stellar Occultation by Comet 67P/Churyumov-Gerasimenko Observed with Rosetta's Alice Far-ultraviolet Spectrograph
Parker, Joel Wm.; Bertaux, Jean-Loup; Stern, S. Alan +13 more
Following our previous detection of ubiquitous {{{H}}}2{{O}} and {{{O}}}2 absorption against the far-ultraviolet continuum of stars located near the nucleus of Comet 67P/Churyumov-Gerasimenko, we present a serendipitously observed stellar occultation that occurred on 2015 September 13, approximately one month after the comet’…
Detection of a Low-mass Stellar Companion to the Accelerating A2IV Star HR 1645
Duchêne, Gaspard; Esposito, Thomas M.; Hom, Justin +51 more
The ∼500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. This signal is consistent with either a stellar companion with a moderate mass ratio (q ∼ 0.5) on a short period (P < 1 yr), or a substellar companion at…
Characterization of Low-mass K2 Planet Hosts Using Near-infrared Spectroscopy
Vanderburg, Andrew; Montet, Benjamin T.; Christiansen, Jessie L. +3 more
We present moderate resolution near-infrared spectra in the H, J, and K band of M-dwarf hosts to candidate transiting exoplanets discovered by NASA’s K2 mission. We employ known empirical relationships between spectral features and physical stellar properties to measure the effective temperature, radius, metallicity, and luminosity of our sample. …
DS Andromedae: A Detached Eclipsing Double-lined Spectroscopic Binary in the Galactic Cluster NGC 752
Frandsen, S.; Milone, E. F.; Schiller, S. J. +1 more
The Wilson-Devinney program has been used to analyze well-calibrated photometric and new radial velocity data to determine the properties and distance of DS Andromedae, a 1.01 day period, double-lined, totally eclipsing binary system of early-F spectral type and a likely member of the intermediate-age open cluster NGC 752. The determinations of ma…
High Spatial Resolution Thermal Infrared Spectroscopy with ALES: Resolved Spectra of the Benchmark Brown Dwarf Binary HD 130948BC
Spalding, Eckhart; Leisenring, Jarron; Woodward, Charles E. +6 more
We present 2.9-4.1 µm integral field spectroscopy of the L4+L4 brown dwarf binary HD 130948BC, obtained with the Arizona Lenslets for Exoplanet Spectroscopy (ALES) mode of the Large Binocular Telescope Interferometer. The HD 130948 system is a hierarchical triple system, in which the G2V primary is joined by two co-orbiting brown dwarfs. By …
Qatar Exoplanet Survey: Qatar-7b—A Very Hot Jupiter Orbiting a Metal-rich F-Star
Bieryla, Allyson; Latham, David W.; Esquerdo, Gilbert A. +18 more
We present the discovery of Qatar-7b—a very hot and inflated giant gas planet orbiting close to its parent star. The host star is a relatively massive main-sequence F-star with mass and radius {M}\star =1.41+/- 0.03 {M}⊙ and {R}\star =1.56+/- 0.02 {R}⊙ , respectively, at a distance d = 726 ± 26 pc, and …
A Hot Saturn Near (but Unassociated with) the Open Cluster NGC 1817
Vanderburg, Andrew; Rampalli, Rayna; Bieryla, Allyson +14 more
We report on the discovery of a hot Saturn-sized planet (9.916 ± 0.985 R ⊕) around a late F-star, K2-308, observed in Campaign 13 of the K2 mission. We began studying this planet candidate because prior to the release of Gaia DR2, the host star was thought to have been a member (≥slant 90 % membership probability) of the ≈ 1 {Gyr} open …