Stop #6 – The Little Dipper and Cepheus

Ursa Minor

Ursa Minor

The Little Dipper

If you’ve found the North Star, then you’ve also found the Little Dipper. Polaris, the North Star, is the end of the handle for the Little Dipper.

The Little Dipper is an asterism, but if viewed differently, it’s also the constellation Ursa Minor, or the Little Bear.  The “handle” of the dipper is the tail of a bear, and the “bowl” of the dipper is the body of the bear.

Ursa Minor Bear

From the Little Dipper, it’s not far at all to Cepheus.

Cepheus

In Greek mythology, Cepheus was the King of Aethiopia (a part of Africa not far from modern-day Ethiopia). Cepheus’s wife was Cassiopeia and their daughter was Andromeda, (both of whom are also have constellations named after them.) Cassiopeia upset Neptune by bragging about how good looking her daughter Andromeda was, so Neptune sent a sea monster to eat Andromeda, but she was saved at the last minute by her future husband, Perseus.

To find this celestial family, we start by looking for the constellation Cepheus, which isn’t far from the Little Dipper.

Cepheus is composed of five main stars: Alderamin, Alfirk, and Errai are the brightest.

Cepheus and the Little Dipper

Cepheus and the Little Dipper

In 1988, a critical astronomical discovery was made in Canada, when three astronomers studying the star Errai in Cepheus reported what would later be confirmed to be the first planet discovered outside of our solar system- what is probably a large planet like Jupiter. We’re not able to see the planet in a telescope yet, but we can track how the planet tugs on it’s sun, Errai, gravitationally.

Errai is also interesting in that, due to the very slow shift of the celestial sphere (known as the “precession of the equinoxes”), it will be the best-positioned star to call the North Star in 1,000 years.