Checked content

File:M3 colour magnitude diagram.jpg

Summary

Colour-magnitude diagram of M3.

Description

This is a color-magnitude diagram for the Messier 3 globular cluster (after A.R. Sandage 1953). The colored points on the chart represent the plotted positions of stars in the cluster. The horizontal scale is based on the B—V colour index of the measured stars.

From the main sequence stars at magnitude 19 and fainter, the plot forms a knee that bends toward the upper right. Based on the position of the knee, the distance modulus for this cluster is determined to be 15.7. The stars along the upper right branch have left the main sequence and entered the red giant stage.

From the red giants branch, a horizontal branch then runs to the left. Note the gap in this branch at visual magnitude 15–16 and spectral type A, where there is a population of variable stars.

Date 12 August 2006
Source The image was drawn using Paint Shop Pro, and is based after a diagram from:
  • Albrecht Unsöld, The New Cosmos, p. 264, Springer-Verlag, New York Inc., 1969.

which in turn credits:

  • W. Baade, Stars and Galaxies, p. 91, Harvard University Press, 1963.

The work by Unsöld is also the reference for the above

description.
Author R. J. Hall
Permission
( Reusing this file)

Creative Commons ShareAlike 1.0 License

Licensing

Creative Commons License
Creative Commons Share Alike icon
This file is licensed under Creative Commons ShareAlike 1.0 License.

The following pages on Schools Wikipedia link to this image (list may be incomplete):

Schools Wikipedia facts

SOS Childrens Villages aims to make Wikipedia suitable for young learners. More than 2 million people benefit from the global charity work of SOS Children's Villages, and our work in 133 countries around the world is vital to ensuring a better future for vulnerable children. Help another child by taking out a sponsorship.