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dc.contributor.authorGeier, S.
dc.contributor.authorKarl, C.
dc.contributor.authorEdelmann, H.
dc.contributor.authorHeber, U.
dc.contributor.authorNapiwotzki, R.
dc.date.accessioned2008-10-03T09:21:07Z
dc.date.available2008-10-03T09:21:07Z
dc.date.issued2008
dc.identifier.citationGeier , S , Karl , C , Edelmann , H , Heber , U & Napiwotzki , R 2008 , Binary sdB Stars with Massive Compact Companions . in Hot Subdwarf Stars and Related Objects - ASP Conf Series 392 . Astronomical Society of the Pacific , pp. 207-214 .
dc.identifier.isbn978-1-58381-654-7
dc.identifier.isbn978-1-58381-655-4
dc.identifier.otherPURE: 175779
dc.identifier.otherPURE UUID: 920ae86e-b82f-4c34-b1d7-dc138328fcc8
dc.identifier.otherdspace: 2299/2426
dc.identifier.urihttp://hdl.handle.net/2299/2426
dc.descriptionOriginal paper can be found at: http://astrosociety.org/pubs/cs/381.html Copyright ASP
dc.description.abstractThe masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with unseen compact companions to derive their masses and clarify their nature. Radial velocity curves were obtained from time resolved spectroscopy. The atmospheric parameters were determined in a quantitative spectral analysis. Based on high resolution spectra we were able to measure the projected rotational velocity of the stars with high accuracy. In the distribution of projected rotational velocities signs of tidal locking with the companions are visible. By detecting ellipsoidal variations in the lightcurve of an sdB binary we were able to show that subdwarf binaries with orbital periods up to 0.6 d are most likely synchronized. In this case, the inclination angles and companion masses of the binaries can be tightly constrained. Five invisible companions have masses that are compatible with that of normal white dwarfs or late type main sequence stars. However, four sdBs have compact companions massive enough to be heavy white dwarfs (> 1M⊙), neutron stars or even black holes. Such a high fraction of massive compact companions is not expected from current models of binary evolution.en
dc.language.isoeng
dc.publisherAstronomical Society of the Pacific
dc.relation.ispartofHot Subdwarf Stars and Related Objects - ASP Conf Series 392
dc.titleBinary sdB Stars with Massive Compact Companionsen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionDepartment of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
rioxxterms.typeOther
herts.preservation.rarelyaccessedtrue


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