SELLEST OSAST
A pair of big, young star clusters is one of the skywatching highlights of autumn evenings. Each cluster contains thousands of stars. And hundreds of those stars are especially impressive – supergiants that are many times the size and mass of the Sun, and many thousands of times brighter.
The clusters are NGC 869 and 884. Together, they’re known as the Double Cluster. They’re in the northeast at nightfall, in the constellation Perseus the hero. Under dark skies, they’re visible to the eye alone as a single smudge of light. Binoculars split them apart, revealing two sparkling collections of stars.
The clusters are more than 7,000 light-years away. They form the core of the Perseus OB1 Association – a huge complex of stars and clouds of gas and dust. The region has given birth to perhaps tens of thousands of stars.
All of the stars were born in the recent past, as measured on the astronomical time scale. The Double Cluster is only about 14 million years old, compared to four-and-a-half billion years for the Sun. One way astronomers determine that age is through the types of stars found in the clusters. The most-massive stars burn out in a hurry. But the clusters still contain many such stars.
Some of those monsters won’t last much longer, though – they’ll blast themselves to bits as supernovas – brilliant light shows in the Double Cluster.
Script by Damond Benningfield
