Stellar Evolution is the process by which stars change throughout their lifetime. The initial mass that a star accumulates during the gravitational collapse of a giant molecular cloud determines how a star will evolve throughout its life. Click on the molecular cloud to learn different evolutionary paths that a star can take!

H-R (or Hertzsprung-Russell) diagrams of star clusters are used by astronomers to study the stars' ages, distances and chemical compositions. An H-R diagram plots the stellar surface temperatures (hotter stars to the left and cooler stars to the right) against the stellar luminosities. Slide the time axis to explore stars through time!

Some of the most common properties astronomers measure to understand stars are age, mass, temperature, luminosity, gravity, and mass loss. Some of these properties have interesting relationships. Explore different stellar property relationships by changing the x and y variables in the dropdown boxes.

Screencast instructions to A Star is Born: Visualizing Stellar Evolution!