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Simultaneous Exosat and VLA Observations of the W UMa Binaries, VW Cep and XY Leo: A Flare on VW Cep

  • Osmi Vilhu
  • Jean-Pierre Caillault
  • James Neff
  • John Heise
Part of the Astrophysics and Space Science Library book series (ASSL, volume 143)

Abstract

We have observed two W UMa-type contact binaries, XY Leo and VW Cep, 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~0.25 days), however, no orbital modulation of either the X-ray or 6 cm data was seen for either star. A large flare from VW Cep was detected, the first such simultaneous flare ever seen on a star other than the Sun. Its behavior before, during, and after the flare is remarkably similar to that found in 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.

Keywords

Solar Flare Impulsive Phase Orbital Modulation Orbital Revolution Large Flare 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1988

Authors and Affiliations

  • Osmi Vilhu
    • 1
    • 2
    • 3
  • Jean-Pierre Caillault
    • 1
    • 2
    • 4
  • James Neff
    • 1
    • 2
  • John Heise
    • 1
    • 2
  1. 1.Joint Institute for Laboratory Astrophysics, National Bureau of StandardsUniversity of ColoradoBoulderUSA
  2. 2.Space Research LaboratoryUtrechtThe Netherlands
  3. 3.Observatory and Astrophysics LaboratoryUniversity of HelsinkiFinland
  4. 4.Department of Physics and AstronomyUniversity of GeorgiaAthensUSA

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