Big Families

The Alpha Persei cluster is a family of more than 500 stars, spanning almost 150 light-years. All of the stars were born at the same time, from the same giant cloud of gas and dust.

Tens of millions of years ago, the family was a lot bigger. Alpha Persei was one of several dozen clusters born in the same nursery. The clusters have all gone their own way. But a recent study supports the idea that they were born together.

Astronomers used observations from the Gaia space telescope. It’s measuring the motions and other details of billions of stars. The astronomers looked at stars in more than 270 young clusters within a few thousand light-years of Earth. The observations allowed the researchers to “rewind” the motions of the clusters. They found that, about 30 million years ago, more than half of the clusters congregated in three “super” clusters. The groups are named for their brightest members – in this case, the Alpha Persei cluster.

The scientists estimated that the three groups have spawned more than 200 massive stellar explosions. The supernovas carved bubbles and shells of gas that span hundreds or thousands of light-years.

The Alpha Persei cluster is near the star Alpha Persei, the brightest star of Perseus. They’re in the northeast at nightfall. Under dark skies, the cluster is visible to the eye alone – a bright member of a scattered family of star clusters.

Script by Damond Benningfield