Search Publications
IRAS 00450+7401 and the Mid-infrared Fade/Burst Cycle of R Coronae Borealis-type Stars
Melis, Carl; Wright, E. L.; Della Costa, John +3 more
We present optical and infrared imaging and spectroscopy of the R Coronae Borealis-type (R Cor Bor) star IRAS 00450+7401. Optical spectra further confirm its classification as a cool R Cor Bor system, having a hydrogen-deficient carbon star spectral subclass of HdC5 or later. Mid-infrared spectroscopy reveals the typical ~8 µm "hump" seen in…
V1507 CYGNI (HD187399): A Highly Evolved, Enigmatic Interacting Binary System with an Eccentric Orbit
Davidge, T. J.
The properties of the interacting, eccentric orbit binary V1507 Cyg (HD187399) are examined with spectra that cover wavelengths from 0.63-0.68 µm. The spectrum of the brightest star is similar to that of the B8 I star β Ori, although with absorption lines that show substructure possibly related to a varying tidal field. The bulk of the Hα em…
Most Rotational Variables Dominated by a Single Bright Feature Are α 2 CVn Stars
Heinze, A. N.; Huber, Mark E.; Flewelling, Heather
We previously reported a rare class of variable star light curves isolated from a sample of 4.7 million candidate variables from the ATLAS survey. Dubbed "UCBH" light curves, they have broad minima and narrow, symmetrical maxima, with typical periods of 1-10 days and amplitudes of 0.05-0.20 mag. They maintain constant amplitude, shape, and phase c…
Observational Constraints on Close Binary Star Evolution. I. Putative Contact Binaries with Long Periods and High Mass Ratios
Kobulnicky, Henry A.; Cook, Evan M.
Evolutionary and structural models for contact binary stars make quantitative predictions about the distribution of systems in the mass ratio (q)-orbital period (P) plane. Specifically, contact binaries containing primaries with convective envelopes are predicted to be absent at mass ratios larger than a critical threshold that is a function of or…
The True Nature of the Brightest Local Triple Stellar Candidates within 100 pc in the Galaxy
Al-Wardat, Mashhoor A.; Annuar, A.; Yousef, Z. T. +1 more
We present a study of a sample of bright (V ≤ 10 mag) and close (d ≤ 100 pc) triple-stellar system candidates in the galaxy, consisting of eight systems in total. Our aim is to determine their actual multiplicity and the physical properties of each stellar component in the systems. The sample was analyzed using a complex spectrophotometric techniq…
Multifilter Time-series Observations of Eleven Blue Short-period ATLAS Variable Stars
Kniazev, A.; Schaffenroth, V.; Koen, C.
Eleven periodic variable stars were observed photometrically through two to four filters from the set UBVR C I C . Phase-folded data for each star cover full cycles of variation. Spectral energy distributions, based on absolute photometry extracted from the literature, are used to inform models of the stars. The stars incl…
Estimation of the Flux at 1450 MHz of OB Stars for FAST and SKA
Jiang, Biwei; Deng, Dingshan; Zijlstra, Albert +2 more
Radio observation is crucial to understanding the wind mechanism of OB stars but very scarce. This work estimates the flux at 1450 MHz (S 1.4GHz) of about 5000 OB stars identified by the LAMOST spectroscopic survey and confirmed by the Gaia astrometric as well as astrophysical measurements. The calculation is performed under the free-fr…
OGLE-2019-BLG-1180Lb: Discovery of a Wide-orbit Jupiter-mass Planet around a Late-type Star
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +32 more
We report on the discovery and analysis of the planetary microlensing event OGLE-2019-BLG-1180 with a planet-to-star mass ratio q ~ 0.003. The event OGLE-2019-BLG-1180 has unambiguous cusp-passing and caustic-crossing anomalies, which were caused by a wide planetary caustic with s ≃ 2, where s is the star-planet separation in units of the angular …
Serverless Architecture for Data Processing and Detecting Anomalies with the Mars Express MARSIS Instrument
Titov, Dmitrij V.; Sánchez-Cano, Beatriz; Pacios, David +4 more
The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board Mars Express has been sampling the topside ionosphere of Mars since mid-2005. The analysis of the main reflection (nadir) of the ionosphere through the ionograms provided by the MARSIS instrument is typically performed manually due to the high noise level in the lower…
CD -27°11535: Evidence for a Triple System in the β Pictoris Moving Group
Kalas, Paul; De Rosa, Robert J.; Macintosh, Bruce +20 more
We present new spatially resolved astrometry and photometry of the CD -27°11535 system, a member of the β Pictoris moving group consisting of two resolved K-type stars on a ~20 yr orbit. We fit an orbit to relative astrometry measured from NIRC2, GPI, and archival NaCo images, in addition to literature measurements. However, the total mass inferre…