Seminars at FGG

Magnetic activity and differential rotation in very young stars in the Kepler field of view

Speaker: Antonio Frasca (INAF-Oss.Astrofisico di Catania )

Date and time: 2011-06-13 10:30

I present a spectroscopic and photometric analysis of young active stars in the field of view of the Kepler space telescope. These stars were selected on the basis of their coronal X-ray activity. In particular, I discuss the case of KIC 8429280, discovered as a very young, active and fast-rotating star through follow-up high-resolution spectroscopy performed with SARG. The analysis of the high-precision Kepler photometry suggests the presence of several surface inhomogeneities in its photosphere, which is differentially rotating with a Sun-like law (equator faster than poles) but with a much higher rotational shear. The high equator-to-pole differential rotation d_Omega ~ 0.27 rad/day is shortly discussed in the context of recent models of differentially rotating stars.