PREDNASAJUCI / LECTURER :

Zdeněk Mikulášek

(1) Department of Theoretical Physics and Astrophysics, Faculty of Science,
Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic


NAZOV / TITLE :

Probing the magnetospheres of chemically peculiar stars through the dips in
their light curves

ABSTRAKT / ABSTRACT :

The advent of extensive photometric surveys such as Kepler,
Corot, TESS, or BRITE missions has enabled the recent unexpected unveiling
of short-term dips in the phase light curves of the majority of magnetic
chemically peculiar stars of the upper main sequence.
We speculate that this characteristic type of stellar variability is caused
by repeating transits of semi-transparent structures of stellar plasma
trapped in the corotating magnetospheres of stars with a global magnetic
field. In the light curves of such stars, we typically observe several dips
with a typical depth from fractions of fractions of mmag to several mmag,
the configuration of which is persistent in the scale of decades. The
occurrence of photometric dips, frequency, and prominence in the light
curves of rotationally modulated objects allows us to judge magnetospheres'
dimension and strength, making this analysis a universally available
instrument for diagnosing stellar magnetic fields.
Dip analysis will be demonstrated using examples of notorious mCP stars such
as V901 Ori, CU Vir, V545 Lyr, 56 Ari, or EE Dra.