Search Results - "Stars"

Most known white dwarfs in multiple systems with main-sequence stars have been discovered with M-type companions, because the white dwarf causes detectable UV excess and bluer colors than expected from a single M star. Surveys have shown that the number of white dwarfs in Sirius-like systems within...

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We present a radial velocity (RV) survey of the field OB and OBe stars of the SMC Wing. We use multiepoch observations of 55 targets obtained with the Magellan Inamori-Magellan Aerial Camera and Spectrograph and M2FS multi-object spectrographs to identify single- and double-lined spectroscopic binar...

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The long and (almost) continuous high-cadence light curves provided by the TESS space mission are ideally suited to study in detail brightness variations in stellar sources on the broad range of timescales between minutes and months. By applying Fourier techniques, even low-amplitude coherent variat...

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Chemically peculiar (CP) stars, particularly CP1 (metallic-line) and CP2 (magnetic Ap/Bp) stars, are crucial for studying microscopic processes in stellar atmospheres, such as atomic diffusion and magnetic interactions. In this study, we present ODCNNnet, a deep learning-based classification model d...

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Identifications of red supergiants (RSGs) in the Milky Way and nearby galaxies have experienced an exponential increase in recent years, driven by advancements in selection techniques, the continued expansion of archival datasets, and a steady increase in spectroscopic data. This review describes th...

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Discordances in radial-velocity measurements of 73 Leonis, made more than a century ago, gave rise to the first suggestion that this fifth-magnitude star was a binary system, but it was 40 yr before an accurate investigation of the object commenced, and a further 25 yr (close to three orbital cycles...

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Runaway stars are defined as stars that depart from their birth clusters at high peculiar velocities. There are two main mechanisms for the formation of runaway stars, i.e., the binary-supernova scenario (BSS) and the dynamical ejection scenario (DES). Investigating the binary fraction of runaway st...

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According to the core fragmentation and dynamical capture theories of binary formation, binaries tend to form with nearly equal masses. The detection of intermediate-mass binaries with low mass ratios challenges these theories, as such binaries may form via disk fragmentation and are very important...

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We present a catalog of 8545 and 19,257 unique DA white dwarfs (WDs) observed in Sloan Digital Sky Survey (SDSS) Data Release 19 and previous SDSS data releases, respectively. This is the largest catalog of both spectroscopic and photometric measurements of DA WDs available to date, and we make this...

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Totally eclipsing contact binaries provide a unique opportunity to accurately determine mass ratios through photometric methods alone, eliminating the need for spectroscopic data. Studying low mass ratio (LMR) contact binaries is crucial for advancing our understanding of binary star evolution and t...

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Classical Ae (CAe) stars are main-sequence, A-type stars with H α emission but no signature of dust. They are thought to be the cool extension of the classical Be stars to lower masses. Recent surveys based on H α spectroscopy have significantly increased the number of known CAe stars, with the popu...

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White dwarf–main-sequence (WD–MS) binary systems are essential probes for understanding binary stellar evolution and play a pivotal role in constraining theoretical models of various transient phenomena. In this study, we construct a catalog of WD–MS binaries using Gaia DR3’s low-resolution BP/RP (X...

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The atmosphere of hypergiant ρ Cas is investigated by the method of atmospheric model. Effective temperature and the surface of gravity are determined by comparing the observed and theoretical values of photometrical indices [c1];Q, and equivalent widths of Balmer lines: Teff = 5450±200K, l...

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This study explores the impact of viscous heating on decretion disks around Classical Ae (CAe) stars, with a focus on modeling the disk’s thermal structure. While photoionization is the dominant heating mechanism, viscous dissipation can play an important role in shaping the disk temperature, partic...

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The Transiting Exoplanet Survey Satellite (TESS) has surveyed nearly the entire sky in full-frame image mode with a time resolution of 200 s to 30 minutes and a temporal baseline of at least 27 days. In addition to the primary goal of discovering new exoplanets, TESS is exceptionally capable at dete...

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We present the discovery and analysis of a nearby eclipsing ultracompact accreting binary SMSS J1138−5139, the first well-constrained LISA-detectable Type Ia supernova progenitor. Our time-series optical spectroscopy identifies its orbital period through radial velocity monitoring at ${P}_{\mathrm{o...

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The individual modes and asymptotic parameters are important characteristics of stellar oscillation. Using TESS 2 minute cadence data from Sectors 1 to 75, we perform asteroseismic analysis of 687 red giants, and provide their oscillation mode parameters. The mode parameters, including frequencies ν...

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The Symbiotic star (SySt) is a long-period interacting binary system, typically consisting of a white dwarf (WD) and a red giant surrounded by a nebula. These systems are natural astrophysical laboratories for investigating binary star evolution. In this paper, we identified nine SySts from the Larg...

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In this research, we conducted systematic photometric, spectroscopic, and theoretical modeling analyses of two δ Scuti stars—KIC 12602250 and KIC 5768203—that pulsate only in radial modes. We collected their relevant photometric and spectroscopic parameters from multiple catalogs and estimated the a...

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