Reiners, Ansgar

Contact Email: areiners@hs.uni-hamburg.de
Institute: Hamburger Sternwarte
Gojenbergsweg 112 D-21029 Hamburg
First Coauthor: J.H.M.M. Schmitt
Institute: Hamburger Sternwarte
Second Coauthor: M. Kürster
Institute: ESO
Research URL:http://www.hs.uni-hamburg.de/german/persons/reiners.html
Presenting Thesis: Yes
Subject Area: Stellar Evolution
Waveband: Optical
Technique: Spectroscopy
Presentation: Oral Contribution: Thursday
Title: Differential rotation in $\psi$ Cap detected through line profile analysis
Abstract: Detection of differential rotation on the F5 dwarf $\psi$Cap using line profile analysis is reported. The Fourier transform of FeI$\lambda$5775 is used to obtain a projected rotational velocity of $v\,\sin{i}\,=\,43\,\pm\,1$kms^-1. A parameter study on the transformed profile showed that limb darkening and turbulence velocities only yield small effects. Combination of equatorial velocity and differential rotation dominates the line profiles' shape. Rigid rotation is shown to be inconsistent with the used profile, a differential effect of $\alpha\,=\,0.15\,\pm\,0.1$ ( $15\,\pm\,10$%) has been found. This is to our knowledge the first time differential rotation was established through line profile analysis. It appears that the differential rotation law is similar to the solar case.