Pulsational and rotational line profile variations of the roAp stars α Cir and HR 3831 ^*

¹ Uppsala Astronomical Observatory, Box 515, S-751 20 Uppsala, Sweden e-mail: oleg@astro.uu.se
² Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia e-mail: ryabchik@inasan.rssi.ru
³ Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria e-mail: ryabchik@tycho.astro.univie.ac.at

Corresponding author: O. Kochukhov, oleg@astro.uu.se

Received: 19 July 2001
Accepted: 22 August 2001

Abstract

We report preliminary results of our new time-resolved high-resolution spectroscopic observations of the roAp stars α Cir and HR 3831. Analysis of pulsational behaviour of individual spectral lines in the 6116-6156 Å spectral region revealed that in both stars it is dominated by the strong rapid variations of the Ndiii 6145.07 Å spectral line. Oscillations of the Ndiii spectral feature are also rotationally modulated. In addition we observed strong rotational modulation of the average HR 3831 line profiles caused by abundance spots on the stellar surface. Weaker rotational modulation was also discovered for the metal lines in the α Cir spectrum. This variability agrees with the rotational period of α Cir obtained from the splitting of the principal pulsation frequency.