Astron. Astrophys. 358, 1001-1006 (2000)

Physical properties of the pulsating hydrogen-deficient star LSS 3184 (BX Cir) ^*

V.M. Woolf and C.S. Jeffery

Armagh Observatory, College Hill, Armagh, BT61 9DG, Ireland (vmw,csj@star.arm.ac.uk)

Received 16 February 2000 / Accepted 3 April 2000

Abstract

We report new determinations of the radius and mass of the pulsating helium-rich, hydrogen-deficient star LSS 3184 (BX Cir) using measurements of radial velocity and angular radius throughout its pulsation cycle. Measurements of radial velocity, and thus changes in stellar radius (), were made using Anglo-Australian Telescope echelle spectra. Hubble Space Telescope ultraviolet spectra and ground-based BV photometry were used to find temperatures and fluxes throughout the pulsation cycle. The temperatures and fluxes were used to find the angular radius of the star (). The , , and values thus found were used to calculate the mean stellar radius . If we use the previously determined for LSS 3184 and our radius estimate, we find its mass to be .

Key words: stars: chemically peculiar stars: oscillations stars: individual: LSS 3184 stars: variables: general

* Based on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by STScI for the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Based on observations obtained at the Anglo-Australian Telescope, Coonabarabran, NSW, Australia

Send offprint requests to: V.M. Woolf

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Contents

• 1. Introduction
• 2. Observations and data reduction
  • 2.1. AAT visible spectral observations
  • 2.2. Hubble Space Telescope ultraviolet observations
• 3. Analysis
  • 3.1. Radial velocity determinations
  • 3.2. Temperature determination
  • 3.3. Radius determination
• 4. Results and discussion
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 20, 2000
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