55 Cancri is a busy star system. It consists of two stars and at least five planets. None of the planets is a good home for life, although there could be undiscovered planets that are more welcoming.

The planets have a couple of sets of names. Their scientific designations are 55 Cancri b, c, d, e, and f. But a few years back, the IAU — the International Astronomical Union — gave them proper names: Galileo, Brahe, Lipperhey, Janssen, and Harriot. They’re named for astronomers, or for lensmakers involved in creating early telescopes.

Astronomers have discovered more than 5,000 planets in other star systems. And hundreds more are added to the list every year. That’s a lot of worlds to name.

The scientific designations take the name of the star — a proper name or a catalog name — and add a letter, starting with b. The letters are applied based on the order in which the planets were discovered.

The IAU has held several contests to pick proper names, and it’s adopted about 150 of the suggestions. They come from scores of countries and cultures — named for people, places, animals, and other sources. And if a system has more than one planet, a single theme is applied to all of the planets — like the planets of 55 Cancri.

The system is in the constellation Cancer, which is in the east at first light. The crab is easy to pick out because it spreads to the upper left of Venus, the “morning star.”
 

Script by Damond Benningfield