Star clusters are packed with stars, but not with planets. So far, only a few dozen of the more than 5600 confirmed exoplanets have been found in clusters. And two of those orbit a single star, in the Beehive Cluster.
The dearth of planets could simply mean that planets are hard to find. Only a small fraction of the stars in the Milky Way Galaxy reside in clusters, and not many clusters are close to us. And clusters can be tightly packed, making it hard to study their individual stars.
But because the stars are so tightly packed, it might be hard to make planets. As stars fly past each other, their gravity could stir up the raw materials for making planets, blocking their birth. And even when a planet is born, a close encounter could kick it away from its star. So maybe there really aren’t many planets in clusters.
The star in the two-planet system in the Beehive is a little smaller and cooler than the Sun, and four billion years younger. One of its planets is about twice the mass of Jupiter, the giant of our own solar system. And it’s so close to the star that it’s extremely hot. The other planet is even bigger, but much farther from the star, so it’s quite cold. So neither planet is a likely home for life.
The system is too faint to see without a telescope. But the Beehive is visible. Under dark skies, it looks like a hazy patch of light. At dawn tomorrow, it’s close to the right or upper right of the Moon.
Script by Damond Benningfield