Age and Initial Helium Abundance of Globular Cluster Stars


IT has already been shown that the number of horizontal branch stars (NHB) relative to the number of red giant stars (NRG) brighter than an appropriate magnitude could be used together with other observable cluster characteristics to estimate the age and initial helium abundance of stars in globular clusters1.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Iben, jun., I., Nature, 220, 143 (1968).

  2. 2

    Faulkner, J., Astrophys. J., 144, 978 (1966).

  3. 3

    Haselgrove, C. B., and Hoyle, F., Mon. Not. Roy. Astro. Soc., 119, 112 (1959).

  4. 4

    Cox, A., and Stewart, J., Astrophys. J. (in the press).

  5. 5

    Eggleton, P. P., Mon. Not. Roy. Astro. Soc. (in the press).

  6. 6

    Iben, jun., I., and Faulkner, J., Astrophys. J., 153, 101 (1968).

  7. 7

    Rood, R., and Iben, jun., I., Astrophys. J., 154, 215 (1968).

  8. 8

    Pavlovskaya, E. D., Variable Stars, 9, 349 (1953).

  9. 9

    Arp, H. C., Astrophys. J., 135, 971 (1962).

  10. 10

    Christy, R. F., Astrophys. J., 144, 108 (1966).

  11. 11

    Iben, jun., I., Astrophys. J., 154, 581 (1968).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

IBEN, I., ROOD, R. Age and Initial Helium Abundance of Globular Cluster Stars. Nature 223, 933–934 (1969).

Download citation

Further reading


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.