A&A 396, 911-916 (2002)
Line profile variations in the Scuti star FG Virginis: A high number of axisymmetric modesL. Mantegazza and E. Poretti
INAF - Osservatorio Astronomico di Brera, Via E. Bianchi 46 23807 Merate, Italy
(Received 26 August 2002 / Accepted 26 September 2002)
Five consecutive nights of high resolution spectroscopic observations of the Scuti star FG Vir allowed us to analyze the radial velocity and line profile variations induced by non-radial multi-mode pulsations. Ten modes were detected. All of them have a photometric counterpart (Breger et al. 1998). Preliminary identifications have been performed by means of the simultaneous fit of line-profile and light variations. Most of these modes have an axisymmetric character ( m=0), one is retrograde (9.20 cd -1, m=1) and one is prograde with a relatively high order (21.55 cd -1, , m=-1). The more accurate results regard the dominant mode (12.72 cd -1) which is axisymmetric with . In this case we were able to obtain reliable estimates of its physical characteristics. The analysis of our data tends to support the idea that the stellar rotation axis probably has a rather low inclination (about ): this is probably the reason for the high number of observed axisymmetric modes. Hence, since the measured is 20.7 km s -1, we deduce that the rotation velocity should be around 80 km s -1 and the rotational period about 1.5 d.
Key words: stars: individual: FG Vir -- stars: oscillations -- stars: variables: Sct -- techniques: spectroscopic
Offprint request: L. Mantegazza, firstname.lastname@example.org
© ESO 2002