Beta Cancri is the brightest star in the constellation, with an apparent magnitude of 3.5.
It is a binary star that consists of an orange K-type giant and a fourteenth magnitude companion 29 arc seconds away. Beta Cancri is approximately 290 light years distant.
The star’s traditional name, Al Tarf (or just Tarf), is believed to be derived either from the Arabic aṭ-ṭarf, which means “the eye,” or aṭ-ṭarfah, which means “the glance (of Leo).”
Acubens, Alpha Cancri, is only the fourth brightest star in Cancer. Its apparent magnitude varies between 4.20 and 4.27.
The star is sometimes also called Al Zubanah or Sertan. The name Al Zubanah comes from the Arabic az-zubānah, which means “claws,” while Sertan is derived from saraţān, which means “the crab.”
Alpha Cancri is a multiple star system located approximately 174 light years from Earth. The brightest component, Alpha Cancri A, is a white A-type main sequence dwarf. The star has an eleventh magnitude companion, Alpha Cancri B. The brighter star in the system is suspected to be a very close binary itself, consisting of two stars separated by 0.1 arc seconds.
Delta Cancri is an orange giant with an apparent magnitude of 3.94. It is 180 light years distant. It is the second brightest star in Cancer. It marks the location of Praesepe (Messier 44), the famous open cluster, also known as the Beehive Cluster.
The star is also notable for its less famous name, Arkushanangarushashutu, which is the longest of all the known star names. It means “the southeast star in the Crab” in ancient Babylonian.
The more commonly used name, Asellus Australis, means “southern donkey colt” in Latin.
Delta Cancri also lies close to the ecliptic and can be occulted by the Moon and, however rarely, by planets.
Gamma Cancri is a white A-type subgiant approximately 158 light years distant. It has an apparent magnitude of 4.66. The star’s traditional name, Asellus Borealis, means “northern donkey colt.” Like Alpha and Delta Cancri, Gamma Cancri is also located near the ecliptic and can be occulted.
Delta and Gamma Cancri, the northern and southern donkey, are usually associated with an old Greek myth. Erastosthenes wrote that, in the war between the gods and the Giants that came after the clash with the Titans, the gods Hephaestus, Dionysus and several others rode on donkeys into battle. The Giants, who had never heard a donkey bray, thought the donkeys were monsters and fled. Dionysus later placed the donkeys in the sky to commemorate the event. He put them next to a star cluster which the Greeks called the Manger (Phatne). The cluster is now known as Praesepe or, more popularly, the Beehive Cluster. (In Latin, praesepe can mean both “hive” and “manger.”)