| Share
 

luminosity

luminosity, in astronomy, the rate at which energy of all types is radiated by an object in all directions. A star's luminosity depends on its size and its temperature, varying as the square of the radius and the fourth power of the absolute surface temperature. The sun is a medium-sized star with a luminosity of 3.8×1033 ergs per sec. The luminosities of other stars are commonly expressed in terms of the sun's luminosity. The known luminosities of stable stars range from about 1/1,000,000 that of the sun for a relatively cool white dwarf to about 1,000,000 times that of the sun for the hottest known supergiant star. See magnitude; mass-luminosity relation; stellar evolution.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on luminosity from Infoplease:

See more Encyclopedia articles on: Astronomy: General

24 X 7

Private Tutor

Click Here for Details
24 x 7 Tutor Availability
Unlimited Online Tutoring
1-on-1 Tutoring