An ultraviolet approach to M 15.
Abstract
The observed UV spectrum of M 15 is reproduced by means of a population synthesis approach in which HB star contribution is derived on the basis of a statistically complete HR diagram that has been transformed into the theoretical plane by means of the Kurucz (1979) conversion tables. Synthetic HBs computed on the basis of theoretical evolutionary tracks substantially reproduce the observed HB pattern, without recourse to ad hoc core rotation, when transformed into the observational plane. A Y value of 0.22 + or - 0.04, and an age of 10 + or - 3 billion years, are found upon comparison of observed and synthetic UV energy distributions.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1983
- Bibcode:
- 1983A&A...121..226N
- Keywords:
-
- Globular Clusters;
- Horizontal Branch Stars;
- Ultraviolet Spectra;
- Astronomical Netherlands Satellite;
- Helium;
- Hertzsprung-Russell Diagram;
- Hot Stars;
- Iue;
- Spectral Energy Distribution;
- Astrophysics