Outbursts of EX Hydrae: mass-transfer events or disc instabilities?
Hellier, C; Kemp, J; Naylor, T; et al.Bateson, FM; Jones, A; Overbeek, D; Stubbings, R; Mukai, K
Date: 1 April 2000
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Monthly Notices of the Royal Astronomical Society
Publisher DOI
Abstract
We present the 45-yr record of the light curve of EX Hya, and discuss the characteristics of its 15 observed outbursts. We then concentrate on the 1998 outburst, reporting the first outburst X-ray observations. We discover an X-ray beat-cycle modulation, indicating that an enhanced accretion stream couples directly with the magnetosphere ...
We present the 45-yr record of the light curve of EX Hya, and discuss the characteristics of its 15 observed outbursts. We then concentrate on the 1998 outburst, reporting the first outburst X-ray observations. We discover an X-ray beat-cycle modulation, indicating that an enhanced accretion stream couples directly with the magnetosphere in outburst, confirming our previous prediction. Optical eclipse profiles late in outburst show that the visible light is dominated by an enhanced mass-transfer stream overflowing the accretion disc. We are uncertain whether the enhanced mass transfer is triggered by a disc instability, or by some other cause. While in outburst, EX Hya shows some of the characteristics of SW Sex stars.
Physics and Astronomy
Faculty of Environment, Science and Economy
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