Why is the constellation cancer called that

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. 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 light years distant.

It has an apparent magnitude of 4. 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. The system is approximately 41 light years distant. This is one of the four known planetary systems known to have at least five planets. The planet nearest to the star is believed to be a terrestrial planet with a mass similar to Neptune, while the outermost planets are believed to be Jovian planets, with masses comparable to that of Jupiter.

Zeta Cancri is a multiple star system approximately It contains at least four stars. They are separated by 1 arc second in the sky. They have an orbital period of 17 years. Lambda Cancri is a blue-white B-type main sequence dwarf, approximately light years distant. It has an apparent magnitude of 5.

Xi Cancri is a spectroscopic binary star approximately light years distant. It is sometimes also known as Nahn. The stars have an orbital period of 4. Brown dwarfs, however, are extremely rare in this cluster, probably because they have been lost by tidal stripping from the halo.

M67 is not the oldest known galactic cluster, but there are very few in the Milky Way known to be older. M67 is an important laboratory for studying stellar evolution, since all its stars are at the same distance and age, except for approximately 30 anomalous blue stragglers, whose origins are not fully understood.

M67 has more than stars similar to the Sun and many red giants, though the total star count has been estimated at over The cluster contains no main sequence stars bluer than spectral type F, since the brighter stars of that age have already left the main sequence. It appears that M67 does not contain an unbiased sample of stars.

One cause of this is mass segregation, the process by which lighter stars actually, systems gain speed at the expense of more massive stars during close encounters, which causes the lighter stars to be at a greater average distance from the center of the cluster or to escape altogether. NGC is a peculiar blend of spiral galaxy with a smooth bulge in the center. The star formation is confined to this ring of tightly wound arms, and the galaxy has been the location of 5 supernovae explosions in the past 30 years!

It is a flare star that has intermittent changes in brightness by up to a five-fold increase. This star is far too faint to be seen with the naked eye, even though it is the 18th closest star system to the Sun at a distance of Also known as Rho1 Cancri, this binary star system is located approximately 41 light-years away from Earth and has a whole solar system of its own!

The system is about 40 light-years away, and is faintly visible to the unaided eye, although you need help to find it. It consists of two wide-spaced stars, one of which is similar to the Sun, and which hosts the planets. The innermost of its planets is a "super Earth," which means it's only a few times heavier than our world -- one of the lightest-weight planets yet discovered.

The other planets are much bigger and heavier. None of the planets is in the star's habitable zone, which is the distance from the star at which liquid water could exist on the surface. Since water is a necessary ingredient for life as we know it, none of the planets is considered a likely abode for life.

Skip to main content. It is a small constellation of faint stars, so it is difficult to find in the sky. This came from a different interpretation of the chemical composition of the star as expressed in the star's spectrum. Meanwhile, the Spitzer Space Telescope was used to monitor the heat emissions from 55 Cancri e. Early results suggested that the planet could be very warm and wet , while follow-ups revealed that the planet is scorching hot and could be oozing lava.

Results released from Spitzer in showed that daytime temperatures on 55 Cancri e can reach as high as 4, degrees Fahrenheit 2, degrees Celsius and about half as much at night — 2, F 1, C. The nature of the surface is still unclear, but researchers did see a hotspot about midway between the day and night sides that is still poorly explained.

The constellation of Cancer represents the giant crab that attacked Hercules during the second of the 12 labors he performed as penance for killing his family.

It was sent by the jealous goddess Hera to thwart Hercules as he battled the water serpent Hydra, but he killed it with his club.