RädlerFest: Alpha Effect and Beyond

Session

Session 16

17 Feb 2011, 16:00

Wenner-Gren Center, floor 7, Hörsalen (Wenner Gren Center)

291. Advection dominated dynamo in solar-type stars: cycle periods and parity selection problem

Prof. Alfio Bonanno

17/02/2011, 16:00

Most probably the sunspot cycle period is ruled by a meridional flow located near the base of the convection zone (Hathaway et al. 2003). On the other hand, if the eddy diffusivity is low enough, dramatic modification of the standard α2Ω-dynamo by the meridional flow are expected. In this paper we shall discuss the dependence of periods, dynamo numbers and the sign of the current...

292. Photometric time series analysis and Doppler imaging of late type stars

Dr Thomas Hackmann

17/02/2011, 16:30

We present surface (Doppler) imaging temperature maps of the FK Comae-type star HD 199178 (V1794 Cyg). The maps have been calculated from high resolution spectra and simultaneous Johnson V-photometry obtained between 1994 and 1997. All maps reveal a high latitude spot, which is 1200-1600 K cooler than the mean surface temperature. The observed slightly flat bottomed absorption lines can...