Simultaneous EXOSAT and VLA observations of the contact binaries VW Cephei and XY Leonis - Quiescent emission and a flare on VW Cephei

Abstract

view Abstract Citations (24) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Simultaneous EXOSAT and VLA Observations of the Contact Binaries VW Cephei and XY Leonis: Quiescent Emission and a Flare on VW Cephei Vilhu, Osmi ; Caillault, Jean-Pierre ; Heise, John Abstract Two W UMa-type contact binaries, XY Leo and VW Cep, were observed simultaneously with Exosat, the VLA, and, in the case of XY Leo, optically. The temporal coverage of each star was sufficient to monitor them throughout two orbital revolutions (P about 0.27 days); however, no orbital modulation of either the X-ray or 6 cm data was seen for either star, indicating large emitting regions. A large flare from VW Cep was detected, the best such simultaneous flare data ever obtained from a star other than the sun. Its behavior before, during, and after the flare was remarkably similar to that found in solar flares, although at 6 cm this flare on VW Cep was about 10,000 times more luminous than typical strong solar flares. For both stars, it is demonstrated that the 6 cm emission cannot be the result of bremsstrahlung radiation of the X-ray emitting plasma; in fact, it is shown, in the case of the VW Cep flare, that the 6 cm emission is consistent with gyrosynchrotron radiation from a source region of order of the system separation. Publication: The Astrophysical Journal Pub Date: July 1988 DOI: 10.1086/166522 Bibcode: 1988ApJ...330..922V Keywords: Eclipsing Binary Stars; Radio Astronomy; Stellar Flares; Stellar Radiation; X Ray Astronomy; Exosat Satellite; Flare Stars; Plasma Radiation; Stellar Spectrophotometry; Very Large Array (Vla); Astrophysics; RADIATION MECHANISMS; STARS: FLARE; STARS: INDIVIDUAL CONSTELLATION NAME: VW CEPHEI; STARS: INDIVIDUAL CONSTELLATION NAME: XY LEONIS; STARS: RADIO RADIATION; STARS: W URSAE MAJORIS; STARS: X-RAYS full text sources ADS | data products SIMBAD (3)