Abstract
WHITE dwarf stars represent the final evolutionary state for most main-sequence stars. They cool slowly enough that even the oldest white dwarfs are still observable in sufficiently deep surveys and they therefore provide a record of the age and star-formation history of the local disk of the Milky Way1–7—and hence a useful constraint on the age of the Galaxy itself. Here we report the initial results of a very deep survey of white dwarfs, that avoids many of the problems associated with the incompleteness of earlier surveys. We use model age–luminosity relations to interpret the luminosity function of our sample of stars, and thus obtain a minimum age for the local Galactic disk of ∼9.5 Gyr. Our results lend weight to an emerging picture of the evolutionary history of the Milky Way, in which the halo formed ∼14–17 Gyr ago8,9, followed by the bulge globular clusters ∼12–14 Gyr ago10, with a modest hiatus before the onset of star formation in the local disk ∼10 Gyr ago.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Winget, D. E. et al. Astrophys. J. 315, L77–L81 (1987).
Iben, I. Jr & Laughlin, G. Astrophys. J. 341, 312–326 (1989).
Wood, M. Astrophys. J. 386, 539–561 (1992).
Schmidt, M. Astrophys. J. 129, 243–258 (1959).
Mestel, L. & Ruderman, M. A. Mon. Not. R. Astron. Soc. 136, 27–38 (1967).
Van Horn, H. Astrophys. J. 151, 227–238 (1968).
Liebert, J., Dahn, C. & Monet, D. Astrophys. J. 332, 891–909 (1988).
Bolte, M. & Hogan, C. J. Nature 376, 399–402 (1995).
Chaboyer, B. Astrophys. J. 444, L9–L12 (1995).
Ortolani, S. et al. Nature 377, 701–704 (1995).
Hintzen, P., Oswalt, T. D., Liebert, J. & Sion, E. M. Astrophys. J. 346, 454–458 (1989).
Oswalt, T. D., Sion, E. M., Hitzen, P. M. & Liebert, J. in White Dwarfs (eds Vauclair, G. & Sion, E.) 379–393 (Kluwer, Dordrecht, 1991).
Oswalt, T. D. et al. in White Dwarfs: Advances in Observation & Theory (ed. Barstow, M.) 419–425 (Kluwer, Dordrecht, 1993).
McCook, G. P. & Sion, E. M. Astrophys. J. Suppl. Ser. (in the press).
Bergeron, P., Wesemael, F. & Beauchamp, A. Publ. Astron. Soc. Pacif. 107, 1047–1054 (1995).
Oswalt, T. D. & Smith, J. A. in White Dwarfs (eds Koester, D. & Wemer, K.) 24–30 (Springer, Berlin, 1995).
Smith, J. A. & Oswalt, T. D. in The Lower Main Sequence—& Beyond (ed. Tinney, C.) 113–119 (Springer, Berlin, 1995).
Ruiz, M. T. & Takamiya, M. Y. Astron. J. 109, 2817–2820 (1995).
Clayton, D. D. Mon. Not. R. Astron. Soc. 234, 1–36 (1988).
Schmidt, M. Astrophys. J. 151, 393–409 (1968).
Ruiz, M. T., Bergeron, P., Leggett, S. K. & Anguita, C. Astrophys. J. 455, L159–L162 (1995).
Bergeron, P., Safgfer, R. & Liebert, J. Astrophys. J. 394, 228–247 (1992).
Bergeron, P. et al. Astrophys. J. 449, 258–279 (1995).
Liebert, J. & Bergeron, P. in White Dwarfs (eds Koester, D. & Werner, K.) 12–18 (Springer, Berlin, 1995).
Eggen, O. J., Lynden-Bell, D. & Sandage, A. R. Astrophys. J. 136, 748–766 (1962).
Truran, J. W. & Theilemann, F. K. in Stellar Populations (eds Norman, C. A., Renzini, A. & Tosi, M.) 149–166 (Cambridge Univ., 1987).
VandenBerg, D. A., Bolte, M. & Stetson, P. Astron. J. 100, 445–468 (1990).
Carney, B. W., Storm, J. & Jones, R. V. Astrophys. J. 386, 663–684 (1992).
Chaboyer, B., Demarque, P. & Sarajedini, A. Astrophys. J. 459, 558–569 (1996).
Pitts, E. & Tayler, R. J. Mon. Not. R. Astron. Soc. 255, 557–560 (1992).
Burkert, A., Truran, J. W. & Hensler, G. Astrophys. J. 391, 651–658 (1992).
Jacoby, G. H. et al. Publ. Astron. Soc. Pacif. 104, 599–662 (1992).
Freedman, W. L. et al. Nature 371, 757–762 (1994).
Pierce, M. J. et al. Nature 371, 385–388 (1994).
van den Bergh, S. Publ. Astron. Soc. Pacif. 106, 1113–1119 (1994).
Probst, R. G. Astrophys. J. Suppl. Ser. 53, 335–350 (1983).
Harrington, R. S. et al. Fifth Catalogue of Trigonometric Parallaxes of Faint Stars (US Naval Obs. Publ. No. XXIV-4, Washington, 1978).
Eggen, O. Astrophys. J. Suppl. Ser. 16, 97 (1968).
Eggen, O. Astrophys. J. Suppl. Ser. 43, 437 (1980).
Schmidt, M. Astrophys. J. 202, 22–29 (1975).
Felten, J. E. Astrophys. J. 207, 700–709 (1976).
Liebert, J., Dahn, C. C. & Monet, D. G. in White Dwarfs (ed. Wegner, G.) 15–23 (Springer, Berlin, 1989).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Oswalt, T., Smith, J., Wood, M. et al. A lower limit of 9.5 Gyr on the age of the Galactic disk from the oldest white dwarf stars. Nature 382, 692–694 (1996). https://doi.org/10.1038/382692a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/382692a0
This article is cited by
-
The evolution of hierarchical triple star-systems
Computational Astrophysics and Cosmology (2016)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
