Bibcode
Hill, C. A.; Watson, C. A.; Steeghs, D.; Dhillon, V. S.; Shahbaz, T.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 459, Issue 2, p.1858-1874
Advertised on:
6
2016
Citations
8
Refereed citations
7
Description
We present a long-term study of the secondary star in the cataclysmic
variable AE Aqr, using Roche tomography to indirectly image starspots on
the stellar surface spanning 8 years of observations. The seven maps
show an abundance of spot features at both high and low latitudes. We
find that all maps have at least one large high-latitude spot region,
and we discuss its complex evolution between maps, as well as its
compatibility with current dynamo theories. Furthermore, we see the
apparent growth in fractional spot coverage, fs, around
45° latitude over the duration of observations, with a persistently
high fs near latitudes of 20°. These bands of spots may
form as part of a magnetic activity cycle, with magnetic flux tubes
emerging at different latitudes, similar to the `butterfly' diagram for
the Sun. We discuss the nature of flux tube emergence in close binaries,
as well as the activity of AE Aqr in the context of other stars.