Determination of stellar rotation with Gaia and effects of spectral mismatch

Abstract

Stellar spectra obtained with Radial Velocity Spectrometer on-board Gaia will enable determination of projected rotational velocities (v sin i) from rotational broadening of spectral lines. To estimate the accuracy with which v sin i can be determined for different stellar types and as a function of magnitude, we perform simulations in which "observed" spectra (as obtained from Gaia RVS simulator) are fitted with Kurucz spectra from template library using the least square method. We compare results on the v sin i accuracy as obtained in the case of spectra differing only in v sin i and in the case of a more general spectral mismatch (in T_eff, log g, [Fe/H]).

6 pages, 5 figures, Proceedings of the Symposium "The Three-Dimensional Universe with Gaia", 4-7 October 2004, Observatoire de Paris-Meudon, France