Radial velocities of giant stars: an investigation of line profile variations. - art. no. 012058
Hekker, S Snellen, I. A. G Aerts, Conny Quirrenbach, A Reffert, S Mitchell, D. S #
Iop publishing ltd
Proceedings of the second helas international conference: helioseismology, asteroseismology and mhd connections vol:118 pages:12058-12058
Journal of Physics Conference Series
International Conference on Helioseismology, Asteroseismology and MHD Connections (HELAS II) Gottingen, GERMANY, AUG 20, 2007-AUG 24, 2008
Since 1999, a radial velocity survey of 179 red giant stars is ongoing at Lick Observatory with a one month cadence. At present similar to 20-100 measurements have been collected per star with an accuracy of 5 to 8 m s(-1). Of the stars monitored, 145 (80%) show radial velocity (RV) variations at a level >20 m s(-1), of which 43 exhibit significant periodicities. Here, we investigate the mechanism causing the observed radial velocity variations. Firstly, we search for a correlation between the radial velocity amplitude and an intrinsic parameter of the star, in this case surface gravity (log g). Secondly, we investigate line profile variations and compare these with theoretical predictions.