Globular Cluster M15 which contains RR Lyrae stars
When we hear the word star, we think of a big flaming ball of gas like our sun. Our sun is a "typical" star, but there are many other types of stars in our galaxy. An example of a different type of star is an RR Lyrae star. These stars belong to a class of different types of variable star, or stars that change their brightness periodically over time. RR Lyrae stars are found in globular clusters, and are more aged and contain less heavy metals than the sun. Reactions in the star's core cause the star to physically pulsate periodically in size, temperature and brightness. They change brightness on the order of days. RR Lyrae stars are being studied by many astronomers so that we can understand and accurately predict the brightness changes of these objects.
Image Credit: Efrain Morales Rivera
