Detecting Chromospheric Activity on the Secondary Star of Cataclysmic Variables
Abstract
Chromospheric activity on the secondary stars of cataclysmic variables (CVs) is a key ingredient for angular momentum loss from the system via magnetic braking. This effect is thought to drive the evolution of the system and is invoked to explain a number of observed properties of CV light curves, such as long-term modulations and high/low states. However, obtaining observational support for this magnetic activity has proven difficult. We present a new method of studying chromospheric activity on the secondary stars of CVs, using near-IR spectral features. We discuss in particular the magnetic CV (polar) AM Herculis, in which satellites to the H-alpha emission line are interpreted as arising from magnetically confined gas streams (prominences). This phenomenon provides a new technique for mapping magnetic structures on CV secondaries, and advances our understanding of the nature of magnetic structures and activity on CV secondaries.
- Publication:
-
Binary Stars as Critical Tools & Tests in Contemporary Astrophysics
- Pub Date:
- August 2007
- DOI:
- 10.1017/S1743921307003961
- Bibcode:
- 2007IAUS..240..154K