Abstract
view Abstract Citations (43) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-Contact Binary Systems in the ROSAT All-Sky Survey Shaw, J. Scott ; Caillault, Jean-Pierre ; Schmitt, J. H. M. M. Abstract We have conducted a survey of near-contact binary systems observed during the ROSAT All-Sky Survey (RASS). The near-contact binaries (NCBs) have an A- or F-type primary, with a companion which is one to two spectral types cooler, The systems have periods less than 1 day and display strong tidal interaction, but they are not in contact like the W UMa systems, There are more than 150 such systems known to exist. We have analyzed the RASS data for all (58) of those known to lie within 400 pc. We report the detection of 14 systems with X-ray count rates >0.01 counts s-1. The X-ray luminosity function for the NCBs derived from this sample is very similar to that for A-type W UMa systems (derived, admittedly, from only a handful of Einstein observations) but appears to be significantly different from those of W-type W UMa systems and RS CVn binaries. This is consistent with the proposed scenario that the NCBs are evolutionary precursors to the A-type W UMa binaries. The mean X-ray luminosity of the NCBs is log LX = 29.3±0.1 ergs s-1, less than that of the RS CVns, but greater than that of normal late-type main-sequence stars. The LX/Lbol values for the handful of stars for which bolometric luminosities could be determined are consistent with their being near saturation. The detection of these systems may help to explain why many presumably single A-type stars were detected in the RASS; i.e., the "single" A stars may, in fact, be binaries, like the NCBs, with late-type companions. Publication: The Astrophysical Journal Pub Date: April 1996 DOI: 10.1086/177116 Bibcode: 1996ApJ...461..951S Keywords: STARS: BINARIES: CLOSE; STARS: BINARIES: ECLIPSING; X-RAYS: STARS full text sources ADS | data products SIMBAD (58)
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
