Mass determination for globular clusters on the basis of proper motions.
Abstract
Published proper motions of stars in the fields of the globular clusters M 15, M 92, and M 13 (Cudworth, 1976; Cudworth and Monet, 1979) are compiled in tables and used to estimate the masses of the clusters by the method of Naumova and Ogorodnikov (1973). Masses of the order of 10 to the 8th solar mass are calculated, as compared to an M 13 mass of about 10 to the 6th solar mass determined by the virial theorem. The higher masses are considered indicative of the actual cluster masses despite the distortion introduced by the presence in the field of stars not belonging to the clusters. It is suggested that the difference between these estimates and the smaller masses proposed by previous authors may represent unobservable peripheral dwarf stars or some invisible mass (like the so-called missing mass of the Galaxy).
- Publication:
-
Astrofizika
- Pub Date:
- March 1984
- Bibcode:
- 1984Afz....20..283N
- Keywords:
-
- Globular Clusters;
- M Stars;
- Stellar Mass;
- Stellar Motions;
- Missing Mass (Astrophysics);
- Stellar Magnitude;
- Virial Theorem;
- Astrophysics