Skip to main content
SpringerLink
Log in

The evolution of helium-rich subdwarf-B stars

  • Published:
Astrophysics and Space Science Aims and scope Submit manuscript

Abstract

Helium-rich subdwarf-B (He-sdB) stars are extremely rare hot subluminous stars found in the field of our Galaxy as well as in some globular clusters. The existence of these hot helium stars cannot be explained by canonical stellar evolution theories nor can it be explained by normal sdB evolution. We discuss the existing evolutionary models for the formation of He-sdB stars—the flash mixing model and the binary white dwarf merger model in the light of new observational results. Spectral classification of objects as He-sdB stars by various authors has resulted in a range of objects, including white dwarfs, being classified as He-sdB stars. We propose a homogeneous definition for this class of objects based on the original classification scheme used in the PG catalogue. Spectral analysis of He-sdB stars in the last 15 years is also briefly reviewed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Aznar Cuadrado, R. and Jeffery, C.S.: 2002,A&A 385, 131.

    Google Scholar 

  • Ahmad, A. and Jeffery, C.S.: 2003, A&A 402, 335.

    Google Scholar 

  • Ahmad, A. and Jeffery, C.S.: 2004, A&A 413, 323.

    Google Scholar 

  • Beers, T.C., Doinidis, S.P., Griffin, K.E., Preston, G.W. and Shectman, S.A.: 1992,AJ 103, 267.

    CAS  Google Scholar 

  • Brown, T.M., Ferguson, H.C., Davidsen, A.F. and Dorman, B.: 1997,ApJ 482, 685.

    CAS  Google Scholar 

  • Brown, T.M., Sweigart, A.V., Lanz, T., Landsman, W.B. and Hubeny, I.: 2001, ApJ 562, 368.

    CAS  Google Scholar 

  • Caloi, V.: 1989,A&A 221, 27.

    Google Scholar 

  • Dreizler, S., Heber, U., Werner, K., Moehler, S. and de Boer, K.S.: 1990,A&A 235, 234.

    Google Scholar 

  • Drilling, J.S.: 1996, in: C.S. Jeffery and U. Heber (eds.), Hydrogen Deficient Stars, ASP Conference Series (vol. 96), 461.

  • Drilling, J.S., Jeffery, C.S., Moehler, S., Heber, U. and Napiwotzki, R.: 2004, A&A in preparation.

  • Green, R.F., Schmidt, M. and Liebert, J.: 1986, ApJS 61, 304.

    Google Scholar 

  • Groth, H.G., Kudritzki, R.P. and Heber, U.: 1985, A&A 152, 107.

    Google Scholar 

  • Harris, H.C., Liebert, J. and Kleinman, S.J., et al.: 2003, AJ 126, 1023.

    CAS  Google Scholar 

  • Heber, U.: 1986, A&A 155, 33.

    Google Scholar 

  • Heber, U., Dreizler, S., de Boer, K.S., Moehler, S. and Richtler, T.: 1988, Astron. Gesellschaft Abstract Series 1, 16.

    Google Scholar 

  • Heber, U., Dreizler, S., Werner, K., Engels, D. and Hagen, H.-J.: 1996, in: C.S. Jeffery and U. Heber (eds.), Hydrogen Deficient Stars, ASP Conference Series (vol. 96), 241.

  • Iben, I.J.: 1990, ApJ 353, 215.

    CAS  Google Scholar 

  • Maxted, P.F.L., Heber, U., Marsh, T.R. and North, R.C.: 2001, MNRAS 326, 1391.

    Google Scholar 

  • Hunger, K., Gruschinske, J., Kudritzki, R.P. and Simon, K.P.: 1981,A&A 95, 244.

    Google Scholar 

  • Moehler, S., Richtler, T., de Boer, K.S., Dettmar, R.J. and Heber, U.: 1990, A&A 86, 53S.

    Google Scholar 

  • Moehler, S., Heber, U. and Durrell, P.R.: 1997, A&A 317, L83.

    Google Scholar 

  • Moehler, S., Sweigart, A.V., Landsman, W.B. and Dreizler, S.: 2002, A&A 395, 37.

    Google Scholar 

  • Jeffery, C.S., Heber, U. and Hill, P.W., et al.: 1996, in Jeffery, C.S. and Heber, U. (eds.), Hydrogen Deficient Stars, ASP Conference Series (vol. 96), 471.

  • Jeffery, C.S., Harrison, P.M. and Drilling, J.S.: 1997,A&A 125, 501.

    Google Scholar 

  • Jeffery, C.S.: 1998, MNRAS 294, 391.

    CAS  Google Scholar 

  • Jeffery, C.S., Woolf, V.M. and Pollacco, D.L.: 2001, A&A 376, 497.

    Google Scholar 

  • Kilkenny, D., Luvhimbi, E., O’Donoghue, D., Stobie, R.S., Koen, C. and Chen, A.: 1995, MNRAS 276, 906.

    Google Scholar 

  • Kilkenny, D., O’Donoghue, D., Koen, C., Stobie, R.S. and Chen, A.: 1997, MNRAS 287, 867.

    CAS  Google Scholar 

  • Saffer, R.A., Bergeron, P., Koester, D. and Liebert, J.: 1994,ApJ 432, 351.

    CAS  Google Scholar 

  • Saio, H. and Jeffery, C.S.: 2000, MNRAS 313, 671.

    CAS  Google Scholar 

  • Saio, H. and Jeffery, C.S.: 2002, MNRAS 333, 121.

    CAS  Google Scholar 

  • Schulz, H., Heber, U. and Wegner G.: 1991, PASP 103, 435.

    Google Scholar 

  • Sweigart, A.V., Lanz, T., Brown, T.M., Hubeny, I. and Landsman,W.B.: 2004, in: P.F.L. Maxted (ed.), Extreme Horizontal Branch Stars and Related Objects, Ap&SS 291, 365.

  • Wesemael, F., Winget, D.E., Cabot, W., van Horn, H.M. and Fontaine, G.: 1982,ApJ 254, 221.

    CAS  Google Scholar 

  • Woolf, V.M. and Jeffery, C.S.: 2000, MNRAS 318, 974.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Armagh Observatory, College Hill, Armagh, BT61 9DG, N. Ireland

    A. Ahmad & C.S. Jeffery

Authors
  1. A. Ahmad
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. C.S. Jeffery
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ahmad, A., Jeffery, C. The evolution of helium-rich subdwarf-B stars. Astrophys Space Sci 291, 253–260 (2004). https://doi.org/10.1023/B:ASTR.0000044329.56416.c2

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/B:ASTR.0000044329.56416.c2

Search

Navigation