Search Publications
Nine Bright γ Doradus Variables Discovered with Ground-based Photometry
Henry, Gregory W.; Williamson, Michael H.; Fekel, Francis C.
We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes b…
Discovery of 16 New Members of the Solar Neighborhood Using Proper Motions from CatWISE2020
Meisner, Aaron M.; Kirkpatrick, J. Davy; Schneider, Adam C. +15 more
In an effort to identify nearby and unusual cold objects in the solar neighborhood, we searched for previously unidentified moving objects using CatWISE2020 proper motion data combined with machine learning methods. We paired the motion candidates with their counterparts in 2MASS, UHS, and VHS. Then we searched for white dwarf, brown dwarf, and su…
An Adaptive Optics Census of Companions to Northern Stars Within 25 pc with Robo-AO
Baranec, Christoph; Law, Nicholas M.; Riddle, Reed +8 more
In order to assess the multiplicity statistics of stars across spectral types and populations in a volume-limited sample, we censused nearby stars for companions with Robo-AO. We report on observations of 1157 stars of all spectral types within 25 pc with decl. >-13° searching for tight companions. We detected 154 companion candidates with sepa…
How Do Spitzer IRAC Fluxes Compare to HST CALSPEC?
Gordon, Karl D.; Hubeny, Ivan; Bohlin, Ralph C. +1 more
An accurate tabulation of stellar brightness in physical units is essential for a multitude of scientific endeavors. The HST/CALSPEC database of flux standards contains many stars with spectral coverage in the 0.115-1 µm range, with some extensions to longer wavelengths of 1.7 or 2.5 µm. Modeled flux distributions to 32 µm for ca…
Constructing the Milky Way Stellar Halo in the Galactic Center by Direct Orbit Integration
Yang, Chengqun; Liu, Chao; Xue, Xiang-Xiang +2 more
The halo stars on highly-radial orbits should inevitably pass the center regions of the Milky Way. Under the assumption that the stellar halo is in "dynamical equilibrium" and is axisymmetric, we integrate the orbits of ~10,000 halo K giants at 5 ≤ r ≤ 50 kpc cross-matched from LAMOST DR5 and Gaia DR3. By carefully considering the selection functi…
TESS Observations of Kepler Systems with Transit Timing Variations
Dalba, Paul A.; Livingston, John H.; Jontof-Hutter, Daniel
We identify targets in the Kepler field that may be characterized by transit timing variations and are detectable by the Transiting Exoplanet Survey Satellite (TESS). Despite the reduced signal-to-noise ratio of TESS transits compared to Kepler, we recover 48 transits from 13 systems in Sectors 14, 15, 26, 40 and 41. We find strong evidence of a n…
Mapping out the Stellar Populations of IC 2602 and IC 2391
Henry, Todd J.; James, Hodari-Sadiki; Jao, Wei-Chun +4 more
IC 2391 and IC 2602 are important benchmarks for testing early star and planet evolution theories, both structural and dynamical, because they are the nearest open clusters with ages of ~50 Myr. We refine membership lists for these clusters by identifying candidate members using Gaia DR2 kinematic and distance information. We identify 451 candidat…
Thermal Phase Curves of XO-3b: An Eccentric Hot Jupiter at the Deuterium Burning Limit
Deming, Drake; Burrows, Adam; Fortney, Jonathan J. +15 more
We report Spitzer full-orbit phase observations of the eccentric hot Jupiter XO-3b at 3.6 and 4.5 µm. Our new eclipse depth measurements of 1770 ± 180 ppm at 3.6 µm and 1610 ± 70 ppm at 4.5 µm show no evidence of the previously reported dayside temperature inversion. We also empirically derive the mass and radius of XO-3b and its…
The Transformative Journey of HD 93521
Gies, Douglas R.; Shepard, Katherine; Klement, Robert +1 more
HD 93521 is a massive, rapidly rotating star that is located about 1 kpc above the Galactic disk, and the evolutionary age for its estimated mass is much less than the time of flight if it was ejected from the disk. Here we present a reassessment of both the evolutionary and kinematical timescales for HD 93521. We calculate a time of flight of 39 …
Bayesian Inference in Single-line Spectroscopic Binaries with a Visual Orbit
Mendez, Rene A.; Clavería, Rubén M.; Orchard, Marcos E. +2 more
We present a Bayesian inference methodology for the estimation of orbital parameters on single-line spectroscopic binaries with astrometric data, based on the No-U-Turn sampler Markov chain Monte Carlo algorithm. Our approach is designed to provide a precise and efficient estimation of the joint posterior distribution of the orbital parameters in …