Astron. Astrophys. 339, 822-830 (1998)

An abrupt decrease in the rotational period of the chemically peculiar magnetic star CU Virginis

D.M. Pyper ¹, T. Ryabchikova ², V. Malanushenko ³, R. Kuschnig ⁴, S. Plachinda ³ and I. Savanov <sup>3

1</sup> University of Nevada-Las Vegas, Physics Department, 4505 Maryland Parkway, Las Vegas, NV 89154-4002, USA (dpsmith@nevada.edu)
² Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia (ryabchik@inasan.rssi.ru)
³ Crimean Astrophysical Observatory, 334413 Nauchny, Crimea, Ukraine (victor@crao.crimea.ua)
⁴ Institute of Astronomy, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna, Austria (kuschnig@galileo.ast.univie.ac.at)

Received 10 September 1997 / Accepted 22 June 1998

Abstract

Spectroscopic and photometric observations of the chemically peculiar star CU Vir over 40 years show that the period of variations decreased by 0.005 % between 1983-1987. The assumption of the rigid rotator model for this star implies an abrupt change of the rotation rate. We find no spectroscopic evidence that the star is a close binary, ruling out a possibility that the period decrease is caused by the mass exchange.

Key words: stars: chemically peculiar stars: variables: other stars: rotation stars: individual: CU Vir

Send offprint requests to: Rainer Kuschnig, (kuschnig@galileo.ast.univie.ac.at)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and reduction
  • 2.1. Photometry
  • 2.2. Equivalent widths and radial velocity measurements
  • 2.3. Magnetic field measurements
• 3. Period search
  • 3.1. Constant period
  • 3.2. Linearily changing period
  • 3.3. Two periods solution
  • 3.4. Does a period change still continue?
• 4. Summary
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: October 22, 1998
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