Publication Abstracts

Simoda and Kimura 1968

Simoda, M., and H. Kimura, 1968: The luminosity function for the globular cluster M13. Astrophys. J., 151, 133-143, doi:10.1086/149424.

The luminosity function for M13 has been obtained down to the visual magnitude 19, by means of star counts on the plates taken with the 74-inch reflector of the Okayama Astrophysical Observatory. Particular attention has been paid to the counting method. A significant difference has been found between our luminosity function and the M3 luminosity function determined by Sandage. Our result for M13 gives a generally steeper gradient when compared with Sandage's result for M3.

By use of our luminosity function and the Population II stellar models given by Icko Iben, Jr., the lifetime and effective helium core mass have been obtained for each evolutionary stage up to the giant tip. Agreement between the present results and the theoretical ones is good, both for the low (Ye = 0.10) and high (Ye = 0.35) helium cases, contrary to the results obtained by Sandage for M3. Lifetimes for the horizontal-branch stars have been found to be 9×107 years for Xe = 0.9 and 5×107 years for Xe = 065. Some evidences which seem to favor the high helium content are discussed.

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BibTeX Citation

  author={Simoda, M. and Kimura, H.},
  title={The luminosity function for the globular cluster M13},
  journal={Astrophys. J.},

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RIS Citation

ID  - si00100w
AU  - Simoda, M.
AU  - Kimura, H.
PY  - 1968
TI  - The luminosity function for the globular cluster M13
JA  - Astrophys. J.
VL  - 151
SP  - 133
EP  - 143
DO  - 10.1086/149424
ER  -

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