What Is a Variable Star?

In 19 23 and 19 24, astronomer edwin hubble started getting observations that would settle the question once and for all. He was studying a nebula known as m 31, which is in the constellation of andromeda. In greek mythology, and Andromeda was an ethiopian princess who married the hero perseus. As hubbell observed the nebula over time, he discovered a particular variable star in it. This type of variable star is known as asepiid variables. There is a direct relationship between how fast a sephiad changes its brightness and how bright it actually is.