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The Little Dipper climbs high across the north on spring nights. It’s anchored on one end by one of the most famous stars in all the night sky: Polaris, the North Star. It’s at the tip of the dipper’s handle.
The other end is anchored by the dipper’s second–brightest star. Kochab marks the top right corner of the dipper’s bowl, and is only a fraction fainter than Polaris.
Kochab is about 130 light-years from Earth. It’s completed its “normal” lifetime, so it’s undergoing a series of changes in its core. Those changes are causing its outer layers to puff up, making the star bigger and brighter. It’s about 40 times wider than the Sun and 130 times brighter. And it’s probably about 1.4 times the Sun’s mass.
Kochab has at least one planet. It’s much heavier than Jupiter, the giant of our own solar system. That means the planet is basically a big ball of gas. It’s much closer to Kochab than Jupiter is to the Sun, though, so the planet’s atmosphere is much hotter than Jupiter’s.
As Kochab continues to age, it’ll get bigger and brighter still, then expel its outer layers into space. That process is likely to strip away some of the planet’s atmosphere — leaving the dead star with a much-reduced companion.
Kochab is high in the north-northeast as night falls, to the upper right of Polaris. It stands directly above Polaris around midnight, and to its upper left at first light, as the Little Dipper wheels around the North Star.
Script by Damond Benningfield