Astron. Astrophys. 326, 692-697 (1997)

Research Note

Complex light variations of the "hybrid" PG 1159 star HS 2324+3944

G. Handler ¹, A. Kanaan ^{2, 3} and M.H. Montgomery <sup>3

1</sup> Institut für Astronomie, Universität Wien, Türkenschanzstraße 17, A-1180 Wien, Austria (gerald@procyon.ast.univie.ac.at)
² Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712, USA
³ Instituto de Fisica, Universidade Federal do Rio Grande do Sul, 90049 Porto Alegre-RS, Brazil

Received 11 March 1997 / Accepted 15 April 1997

Abstract

We present 17.36 hours of new time-series photometric observations of the variable "hybrid" PG 1159 star HS 2324+3944. These data allow us to demonstrate the presence of four frequencies in the light variations with evidence for more. The dominating time scale of the variability (around 35 minutes) is much longer than that of GW Vir pulsators.

Binarity is not likely to cause the object's light variations. A pulsational origin of the variability seems more attractive. Recent theoretical investigations suggest that pre-white dwarf pulsations can be excited despite the presence of hydrogen in the model's driving region.

Key words: stars: oscillations -- stars: individual: HS 2324+3944 -- stars: white-dwarfs

Send offprint requests to: G. Handler

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Contents

• 1. Introduction
• 2. Data acquisition and reduction
  • 2.1. CCD observations
  • 2.2. Photoelectric observations
• 3. Frequency analysis
• 4. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: October 15, 1997
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