Hostname: page-component-76fb5796d-wq484 Total loading time: 0 Render date: 2024-04-30T05:58:00.038Z Has data issue: false hasContentIssue false
  • English
  • Français

The long secondary periods in semi-regular variables

Published online by Cambridge University Press:  12 April 2016

P.R. Wood ,
A.E. Olivier  and
S.D. Kawaler
P.R. Wood
Affiliation:
Research School of Astronomy & Astrophysics, Australian National University, Cotter Road, Weston Creek ACT 2611, Australia
A.E. Olivier
Affiliation:
Research School of Astronomy & Astrophysics, Australian National University, Cotter Road, Weston Creek ACT 2611, Australia
S.D. Kawaler
Affiliation:
Department of Physics and Astronomy, Iowa State University, Ames IA 50011, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

About 25% of variable asymptotic giant branch stars in the LMC have light curves that are modulated by a long secondary period of length ~ 1–4 yr. Solar-vicinity analogs of these stars show radial velocity curves that are asymmetric and of small amplitude (~3–5km s−1). Possible explanations for the photometric and radial velocity variations include: eccentric motion of an orbiting companion of mass ~0.1 M⊙; radial and nonradial pulsation; rotation of an ellipsoidal-shaped red giant; episodic dust ejection; and star spot cycles. We find that there are severe difficulties with each of these models. Thus, the long secondary periods are the only unexplained type of large-amplitude stellar variability known at this time.

Type
Part 5. Red Giants, Miras, post-AGB stars and proto-planetary nebulae
Information
International Astronomical Union Colloquium , Volume 193: Variable Stars in the Local Group , 2004 , pp. 322 - 326
Copyright
Copyright © Astronomical Society of the Pacific 2004

References

Hinkle, K.H., Lebzelter, T., Joyce, R.R., Fekel, F.C. 2002, AJ, 123, 1002 Google Scholar
Höfner, S., Feuchtinger, M.U., Dorfi, E.A. 1995, A&A, 297, 815 Google Scholar
Houk, N. 1963, AJ, 68, 253 Google Scholar
Kiss, L.L., Szatmáry, K., Cadmus, R.R. Jr, Mattei, J.A. 1999, A&A, 346, 542 Google Scholar
Luttermoser, D.G., Johnson, H.R. Eaton, J. 1994, ApJ, 422, 351 Google Scholar
Olivier, E.A., Wood, P.R. 2003, ApJ, 584, 1035 CrossRefGoogle Scholar
Payne-Gaposhkin, C. 1954, Harvard Annals, 113, No. 4 Google Scholar
Percy, J.R., Bakos, G.A. 2003, preprintGoogle Scholar
Winters, J.M., Fleischer, A.J., Gauger, A., Sedlmayr, E. 1994, A&A, 290, 623 Google Scholar
Wood, P.R. and the MACHO COLLABORATION 1999, in IAU Symposium 191, AGB Stars, eds. Le Bertre, T., Lèbre, A. & Waelkens, C. (San Francisco, ASP), 151 Google Scholar
Wood, P.R. 2000, in IAU Coll. 176, ASP Conf. Ser. Vol. 203, The Impact of Large-Scale Surveys on Pulsating Star Research, eds Szabados, L. & Kurtz, D. (San Francisco, ASP), 379 Google Scholar
Wood, P.R., Olivier, E.A., Kawaler, S. 2003, ApJ, submittedGoogle Scholar