Research Note

The Hvar survey for roAp stars

II. Final results

¹ Department of Theoretical Physics and AstrophysicsMasaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
e-mail: epaunzen@physics.muni.cz
² Institut für Astrophysik der Universität Wien, Türkenschanzstr. 17, 1180 Wien, Austria
³ Copernicus Astronomical Center, Bartycka 18, 00-716, Warsaw, Poland
⁴ Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kačićeva 26, 10000 Zagreb, Croatia

Received: 5 November 2014
Accepted: 14 January 2015

Abstract

Context. The 60 known rapidly oscillating Ap (roAp) stars are excellent laboratories to test pulsation models in the presence of stellar magnetic fields. Our survey is dedicated to search for new group members in the northern hemisphere.

Aims. We attempt to increase the number of known chemically peculiar stars that are known to be pulsationally unstable.

Methods. About 40 h of new CCD photometric data of 21 roAp candidates, observed at the 1 m Austrian-Croatian Telescope (Hvar Observatory) are presented. We carefully analysed these to search for pulsations in the frequency range of up to 10 mHz.

Results. No new roAp star was detected among the observed targets. The distribution of the upper limits for roAp-like variations is similar to that of previoius similar efforts using photomultipliers and comparable telescope sizes.

Conclusions. In addition to photometric observations, we need to consolidate spectroscopic information to select suitable targets.