A Caltech Library Service

A Study of the Globular Cluster M3


Sandage, Allan Rex (1953) A Study of the Globular Cluster M3. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/06G7-RG84.


NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The color-magnitude diagram for the globular cluster M3 has been obtained to absolute magnitude M[subscript v] = +6. The main sequence has been found, extending from M[subscript v] = +3.5 to the limit of the data. The photometric parallax of m - M = 15.63 is found by fitting the apparent magnitude diagram to O. J. Eggen's and H. L. Johnson's diagram for stars in the solar neighborhood. The absolute magnitude of the cluster type variables in M3 is calibrated by this method. The value M[subscript v]= 0.0 for these stars is correct within [...]. This value is of significance for a decision on a new distance scale for the extragalactic nebulae in the observable universe. The luminosity function is obtained to M[subscript v] = 6.8 for M3. From M[subscript Bol]= +2 to +4 a linear relation between log [...] (M) and M[subsript Bol] exists. The results of Chapter 3 show that this relation is expected if the sequences of the color-magnitude diagram are evolutionary in origin. Application of a theory of evolution to the color magnitude diagram gives an age of 5 x 10[superscript 9] years since the formation of the main sequence in M3 and M92. Further consequences of an evolutionary interpretation of the data are discussed in Chapter 3 and it is concluded that all evidence now available lends support to the evolutionary explanation of the sequences in the color-magnitude diagram.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Astronomy and Physics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astronomy
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Baade, Walter
Group:Astronomy Department
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 April 1953
Record Number:CaltechETD:etd-10212002-160549
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4199
Deposited By: Imported from ETD-db
Deposited On:22 Oct 2002
Last Modified:25 May 2023 21:38

Thesis Files

PDF (Sandage_ar_1953.pdf) - Final Version
See Usage Policy.


Repository Staff Only: item control page