Abstract
The relation between photospheric and coronal active regions in late–type stars is studied from two different points of departure. First, I report on 5 years of ROSAT X–ray monitoring of the active young K–star AB Dor. I compare the X–ray data with 16 years of V–band brightness monitoring showing a 10–year decline between 1978 and 1989 and a subsequent rise phase. Quite differently, the X–ray flux of AB Dor (while exhibiting strong variability on time scales of minutes to weeks) reveals no pronounced long–term trend over the 5 years of the program. This supports the concept of a saturated corona. Second, I present rotationally modulated ROSAT X–ray light curves of three active stars (AB Dor, CF Tuc, YY Men) and compare them with contemporaneous Doppler images. I demonstrate that it is possible to explain the X–ray light curves by coronal emission regions that are spatially related with photospheric active regions. I discuss the concept of X–ray bright loops connecting the major star spot complexes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
