Search Publications
X-Ray and UV Observations of the Contact Binary KIC 9832227
Pandel, Dirk; Molnar, Lawrence A.
We investigate the X-ray and UV emission from the contact binary star KIC 9832227, which was observed with XMM-Newton for one orbital cycle. The binary is detected with an average X-ray luminosity of 3.4 × 1030 erg s-1. The X-ray emission is restricted to energies below 3 keV and originates from a multitemperature plasma with…
Mass Ratio of Single-line Spectroscopic Binaries with Visual Orbits Using Bayesian Inference and Suitable Priors
Vanzi, Leonardo; Anguita-Aguero, Jennifer; Mendez, Rene A. +4 more
We present orbital elements for 22 single-line binaries, nine of them studied for the first time, determined from a joint spectroscopic and astrometric solution. The astrometry is based on interferometric measurements obtained with the HRCam Speckle camera on the SOAR 4.1 m telescope at Cerro Pachon, Chile, supplemented with historical data. The s…
Chemical Compositions Of Red Giant Stars in the Old Open Cluster NGC 7789
Pilachowski, Catherine A.; Afşar, Melike; Sneden, Christopher +1 more
We have gathered optical-region spectra, derived model atmosphere parameters, and computed elemental abundances for 15 red giant stars in the open cluster NGC 7789. We focus on the light element group CNOLi that provides clues to evolutionary changes associated with internal fusion events and chemical mixing. We confirm and extend an early report …
Two Warm Super-Earths Transiting the Nearby M Dwarf TOI-2095
Kostov, Veselin B.; Powell, Brian P.; Barclay, Thomas +56 more
We report the detection and validation of two planets orbiting TOI-2095 (TIC 235678745). The host star is a 3700 K M1V dwarf with a high proper motion. The star lies at a distance of 42 pc in a sparsely populated portion of the sky and is bright in the infrared (K = 9). With data from 24 sectors of observation during Cycles 2 and 4 of the Transiti…
Timescale of Stellar Feedback-driven Turbulence in the ISM: A Deep Dive into UGC 4305
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Cohen, Roger E. +3 more
Understanding the interplay of stellar feedback and turbulence in the interstellar medium (ISM) is essential to modeling the evolution of galaxies. To determine the timescales over which stellar feedback drives turbulence in the ISM, we performed a spatially resolved, multiwavelength study of the nearby star-forming dwarf galaxy UGC 4305. As indic…
TU Tau B: The Peculiar "Eclipse" of a Possible Proto-barium Giant
Walker, Gary; Gray, Richard O.; Corbally, Christopher J. +26 more
TU Tau (=HD 38218 = HIP 27135) is a binary system consisting of a C-N carbon star primary and an A-type secondary. We report on new photometry and spectroscopy which tracked the recent disappearance of the A-star secondary. The dimming of the A star was gradual and irregular, with one or more brief brightenings, implying the presence of nonhomogen…
Catalog of Integrated-light Star Cluster Light Curves in TESS
Davenport, James R. A.; Pepper, Joshua; Fetherolf, Tara +10 more
We present the first integrated-light, TESS-based light curves for star clusters in the Milky Way, Small Magellanic Cloud, and Large Magellanic Cloud. We explore the information encoded in these light curves, with particular emphasis on variability. We describe our publicly available package elk, which is designed to extract the light curves by ap…
The Origin of the Large Magellanic Cloud Globular Cluster NGC 2005
Piatti, Andrés E.; Hirai, Yutaka
The ancient Large Magellanic Cloud (LMC) globular cluster NGC 2005 has recently been reported to have an ex situ origin, thus, setting precedents that the LMC could have partially formed from smaller merged dwarf galaxies. We here provide additional arguments from which we conclude that is also fairly plausible an in situ origin of NGC 2005, based…
A Census of the Most Luminous Stars. I. The Upper HR Diagram for the Large Magellanic Cloud
Humphreys, Roberta M.; Martin, John C.
Spectral classification and multiwavelength photometry for the most luminous stars in the LMC has greatly increased due to several recent surveys for both the hottest and coolest members. Combining data from these spectroscopic and photometric surveys, we have created catalogs based on their spectral classifications of the different groups: the lu…
LAMOST J2043+3413-a Fast Disk Precession SW Sextans Candidate in Period Gap
Wang, Xiaofeng; Liu, Jiren; Sun, Yongkang +5 more
We present follow-up photometric observations and time-series analysis of a nova-like, SW Sextans-type, cataclysmic variable (CV) candidate, LAMOST J204305.95+341340.6 (hereafter J2043+3413), with a Gaia G-band magnitude of 15.30 and a distance of 990 pc, which was identified from the LAMOST spectrum. The photometric data were collected with the T…