Chandra Observations of the Eclipsing Wolf-Rayet Binary CQ CepOver a Full Orbital Cycle
- Autor(en)
- Steve L. Skinner, Manuel Guedel, Werner Schmutz, Svetozar Zhekov
- Abstrakt
We present results of Chandra X-ray observations and simultaneous optical light curves of the short-period (1.64 d) eclipsing WN6+O9 binary system CQ Cep obtained in 2013 and 2017 covering a full binary orbit. Our primary objective was to compare the observed X-ray properties with colliding wind shock theory, which predicts that the hottest shock plasma (T > 20 MK) will form on or near the line-of-centers between the stars. Thus, X-ray variability is expected during eclipses when the hottest plasma is occulted. The X-ray spectrum is strikingly similar to apparently single WN6 stars such as WR 134 and spectral lines reveal plasma over a broad range of temperatures T ~ 4 - 40 MK. Both primary and secondary optical eclipses were clearly detected and provide an accurate orbital period determination (P = 1.6412 d). The X-ray emission remained remarkably steady throughout the orbit and statistical tests give a low probability of variability. The lack of significant X-ray variabililty during eclipses indicates that the X-ray emission is not confined along the line-of-centers but is extended on larger spatial scales, contrary to colliding wind predictions.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- University of Northern Colorado, Physikalisch-Meteorologische Observatorium, Netherlands Institute for Radio Astronomy (ASTRON)
- Publikationsdatum
- 06-2018
- ÖFOS 2012
- 103003 Astronomie, 103004 Astrophysik
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/50892ab0-aae4-48d0-9c19-08588e5299d2