* Astronomy

One of the most distant stars thats visible to the unaided eye is also one of the most dramatic. A few years ago, astronomers watched as the star blasted hot gas into space -- enough material to make up all the planets and moons in our solar system 20 times over.
The star is called Rho Cassiopeia -- Rho Cas for short. Its in Cassiopeia, the queen, which stands high in the north at nightfall. The constellation forms a letter M or W, which stands high in the north as darkness falls right now. Rho Cas is to the left of the M, or right of the W.

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Position(2000): RA 23h 54m 23.0s Dec +57° 29 58

Rho Cassiopeiae ( Cas, Rho Cas, 7 Cas, HR 9045, HIP 117863, HD 224014, BD+56 3111, SAO 35879, FK5 899, and SV* HV 194.) is a yellow hypergiant in the constellation Cassiopeia. It is about 11650 light-years away, yet can still be seen by the naked eye (in the Northern Hemisphere only), as it is 550,000 times as luminous as the Sun. Its surface diameter is 450 times that of our sun's. On average, it has an absolute magnitude of 7.5, making it one of the most luminous stars known. Even though its surface temperature is similar to the Sun, its comfort zone for an Earthlike planet would be an incredible 450AU.
Rho Cassiopeiae is somewhat unstable in its luminosity. Its apparent magnitude is at about 4.5, but in 1946 it dimmed to the 6th magnitude, before going returning to its previous brightness. This happened again in 20002001, when it produced one of the largest outbursts known, ejecting 3% of a Solar-mass, the equivalent of 10,000 Earths. During the summer of 2000 it was observed (by the William Herschel Telescope) to have cooled from 7000 to 4000 degrees in the course of a few months. It seems to undergo these eruptions approximately once every 50 years (data suggests previous eruptions in 1893 and 1945).

Astronomers predict Rho Cassiopeiae may become a supernova in the near future because it will soon have consumed most of its nuclear fuel.

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