Mass and Luminosity

For low mass stars, the relation between their luminosity (intrinsic energy output) and their mass is the following:

L α M4
(Luminosity is proportional to mass to the fourth power)

  1. A one solar mass star has a luminosity of one solar luminosity.

Discussion

Be able to explain how astronomers first determined mass-luminosity relationship of stars. What properties did they notice in order to determine the mass?