Astron. Astrophys. 331, 1022-1036 (1998)

Wolf-Rayet stars and O-star runaways with HIPPARCOS

II. Photometry ^*

S.V. Marchenko ¹, A.F.J. Moffat ¹, K.A. van der Hucht ², W. Seggewiss ³, H. Schrijver ², B. Stenholm ⁴, I. Lundström ⁴, D.Y.A. Setia Gunawan ^{2, 5}, W. Sutantyo ⁶, E.P.J. van den Heuvel ⁷, J.-P. De Cuyper ⁸ and A.E. Gómez <sup>9

1</sup> Département de Physique, Université de Montréal, C.P. 6128, Succ. "Centre-Ville", Montréal, Qc, H3C 3J7, and Observatoire du mont Mégantic, Canada (sergey,moffat@astro.umontreal.ca)
² Space Research Organization Netherlands, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands (k.vanderhucht,j.schrijver,diah@sron.ruu.nl)
³ Universitäts-Sternwarte Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany (seggewis@astro.uni-bonn.de)
⁴ Lund Observatory, P.O. Box 43, S-22100 Lund, Sweden (bjorn,ingemar@astro.lu.se)
⁵ Kapteyn Astronomical Institute, P.O. Box 800, 9700 AV Groningen, The Netherlands
⁶ Observatorium Bosscha and Jurusan Astronomi, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia (winardi@ibm.net)
⁷ Astronomical Institute "Anton Pannekoek", Kruislaan 403, 1098 SJ Amsterdam, The Netherlands (edvdh@astro.uva.nl)
⁸ Koninklijke Sterrenwacht van Belgiï, Ringlaan 3, B-1180 Brussel, Belgium (jean-pierre.decuyper@oma.be)
⁹ Observatoire de Paris-Meudon, D.A.S.G.A.L., F-92195 Meudon Cedex, France (anita@mehipa.obspm.fr)

Received 19 September 1997 / Accepted 2 December 1997

Abstract

Abundant HIPPARCOS photometry over 3 years of 141 O and Wolf-Rayet stars, including 8 massive X-ray binaries, provides a magnificent variety of light curves at the 1-5% level. Among the most interesting results, we mention: optical outbursts in HD 102567 (MXRB), coinciding with periastron passages; drastic changes in the light curve shape of HD 153919 (MXRB); previously unknown long-term variability of HD 39680 (O6V:[n]pe var) and WR 46 (WN3p); unusual flaring of HDE 308399 (O9V); ellipsoidal variations of HD 64315, HD 115071 and HD 160641; rotationally modulated variations in HD 66811= Pup (O4Inf) and HD 210839= Cep (O6I(n)fp); dust formation episode in WR 121 (WC9). In a statistical sense, the incidence of variability is slightly higher among the WR stars, which might be explained by the higher percentage of known binary systems. Among the presumably single WR stars, the candidate runaways appear to be more variable then the rest.

Key words: stars: activity stars: variables: other stars: Wolf-Rayet

* Based on data from the ESA Hipparcos astrometry satellite

Send offprint requests to: S.V. Marchenko

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Contents

• 1. Introduction
• 2. Data reduction and period search
• 3. Results
  • 3.1. MXRB
  • 3.2. Candidate O-star runaways
  • 3.3. Wolf-Rayet stars
• 4. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: March 3, 1998
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