Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Mass-Luminosity formula
Name: Matt L Rasmussen
Status: Other
Age: N/A
Location: N/A
Country: N/A
Date: N/A 

What is the formula for mass-luminosity relation?

The various sources I have looked at do not give an equation as such; they merely state that if you graph Log(L) versus Log(M) for a number of stars on the main sequence, they tend to lie in a fairly thin band. But as the Encyclopedia of Physical Science and Technology points out, during the course of a star's lifetime its luminosity varies considerably, whereas its mass remains nearly constant; so it is clear that no single equation will work for all stars at all stages of stellar evolution. The above-mentioned source says that L increases approximately as M^3 for stars on the order of 10 solar masses, as M^4.5 for stars of around 1 solar mass, and as M^2 for low-mass stars. Further, this is only good for stars that have "just" entered the main sequence.

RC Winther

Click here to return to the Astronomy Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory