Sonoma State University

Astronomy 100
J.S. Tenn

Properties of Stars

We measure

Brightness B or apparent magnitude

Distance d

Color Index B - V or spectral class OBAFGKMLT

Orbital parameters of binary systems

From these we infer

Luminosity L or absolute magnitude

Surface temperature T

Radius R

Mass M

Average density  

We seek correlations by plotting

Absolute magnitude or luminosity vs. color index or spectral class (Hertzsprung-Russell Diagram) (interactive version)

Mass vs. luminosity (Mass-luminosity relation)

For further information on stars, see the Stars website of Prof. James B. Kaler of the University of Illinois.

Please send comments, additions, corrections, and questions to
joe.tenn@sonoma.edu
JST
2003-03-28