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200 papers

182 single-lined hot subdwarf stars are identified by using spectra from the sixth and seventh data release (DR6 and DR7) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) survey. We classified all the hot subdwarf…

Solar and Stellar Astrophysics · Physics 2020-02-12 Zhenxin Lei , Jingkun Zhao , Péter Németh , Gang Zhao

We present an updated version of the spectroscopic catalogue of white dwarf-main sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS). We identify 939 WDMS binaries within the data releases (DR) 9-12 of SDSS plus 40 objects…

Solar and Stellar Astrophysics · Physics 2016-03-23 A. Rebassa-Mansergas , J. J. Ren , S. G. Parsons , B. T. Gaensicke , M. R. Schreiber , E. Garcia-Berro , X. -W. Liu , D. Koester

Observations from the Heliospheric Imagers (HI-1) on both the STEREO spacecraft have been analysed to search for bright low mass eclipsing binaries (EBs) and potential brown dwarf transits and to determine the radii of the companions. A…

Solar and Stellar Astrophysics · Physics 2015-06-11 K. T. Wraight , L. Fossati , Glenn J. White , A. J. Norton , D. Bewsher

Using the recently published Gaia second data release which includes measurements of the mean radial velocity of about 7.2 million stars, we performed a systematic comparison with other existing radial velocity catalogues in order to search…

Solar and Stellar Astrophysics · Physics 2019-07-17 D. Jack

We measured projected rotational velocities of more than a hundred apparently single sdBs. A comparison is made with sdB stars in binary systems with orbits so wide, that tidal interaction becomes negligible. All of these stars are slow…

Solar and Stellar Astrophysics · Physics 2011-12-14 S. Geier , U. Heber , H. Edelmann , R. Napiwotzki , L. Morales-Rueda

We study the distribution of exoplanets around main sequence (MS) stars and apply our results to the binary model for the formation of extreme horizontal branch (EHB; sdO; sdB; hot subdwarfs) stars. By Binary model we refer both to stellar…

Solar and Stellar Astrophysics · Physics 2015-05-18 Ealeal Bear , Noam Soker

We have surveyed a sample of 165 solar-type spectroscopic binaries (SB) with periods from 1 to 30 days for higher-order multiplicity. 62 targets have been observed with the NACO adaptive optics system and 13 new physical tertiary companions…

Astrophysics · Physics 2009-11-11 A. Tokovinin , S. Thomas , M. Sterzik , S. Udry

Using measured radial velocity data of nine double lined spectroscopic binary systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via the…

Astrophysics · Physics 2008-12-18 K. Karami , R. Mohebi , M. M. Soltanzadeh

Hot subdwarf B (sdB) stars are evolved, subluminous, helium-burning stars, most likely formed when red-giant stars lose their hydrogen envelope via interactions with close companions. They play an important role in our understanding of…

Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of Be stars owe their rapid rotation to mass and angular-momentum transfer in…

The survey of radial velocity orbits for short period (P < 1 day), bright (V < 10, with a few fainter stars) conducted at the David Dunlap Observatory in the last 9 years before its closure in 2008 included 162 binaries and resulted in 150…

Solar and Stellar Astrophysics · Physics 2010-10-07 Slavek M. Rucinski

Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which lost almost all of their hydrogen envelopes. This mass loss is often triggered by common envelope interactions with close stellar or even substellar companions. Cool…

Solar and Stellar Astrophysics · Physics 2018-06-20 V. Schaffenroth , S. Geier , U. Heber , R. Gerber , D. Schneider , E. Ziegerer , O. Cordes

The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire…

Astrophysics · Physics 2007-05-23 P. North , N. Ginestet , J. -M. Carquillat , F. Carrier , S. Udry

The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M > 1.0 Msun), neutron stars or stellar mass black…

Context. This work is part of a long-term spectroscopic study of a sample of 30 multiple stars with early-type components. In this second paper we present the results of six multiple systems in which new stellar components have been…

Solar and Stellar Astrophysics · Physics 2014-09-05 M. E. Veramendi , J. F. González

Hot subdwarf B stars (sdBs) are core helium-burning stars located on the extreme horizontal branch. About half of the known sdB stars are found in close binaries. Their short orbital periods of 1.2 h to a few days suggest that they are post…

Solar and Stellar Astrophysics · Physics 2014-05-08 V. Schaffenroth , S. Geier , U. Heber , T. Kupfer , E. Ziegerer , C. Heuser , L. Classen , O. Cordes

The Gaia mission is delivering a large number of astrometric orbits for binary stars. By combining these with spectroscopic orbits for systems with two observable spectra (SB2), it is possible to derive the masses of both components.…

Solar and Stellar Astrophysics · Physics 2023-12-15 Thibault Merle , Dimitri Pourbaix , Alain Jorissen , Christos Siopis , Sophie Van Eck , Hans Van Winckel

Hot subdwarf B stars (sdBs) in close binary systems are assumed to be formed via common envelope ejection. According to theoretical models, the amount of energy and angular momentum deposited in the common envelope scales with the mass of…

Solar and Stellar Astrophysics · Physics 2015-05-27 S. Geier , R. Napiwotzki , U. Heber , G. Nelemans

Context: Hot subdwarf B stars (sdBs) are considered to be core helium-burning stars with very thin hydrogen envelopes situated on or near the extreme horizontal branch (EHB). The formation of sdBs is still unclear as well as the chemical…

Solar and Stellar Astrophysics · Physics 2015-06-12 S. Geier

Observations have definitively strengthened the long-standing assertion that binaries are crucial in massive star evolution. While the percentage of spectroscopic binary systems among main-sequence O stars is well-studied, other phases of…

Solar and Stellar Astrophysics · Physics 2024-05-21 S. Simón-Díaz , N. Britavskiy , N. Castro , G. Holgado , A. de Burgos