51 Pegasi

51 Pegasi is a star that is like our Sun. It is 15.4 parsecs (50.1 light-years) away from the Earth in the constellation Pegasus. 

It was the first Sun-like star, other than the Sun, found to have a planet orbiting it.NASA In 1996 astronomers Baliunas, Sokoloff, and Soon calculated that it takes 51 Pegasi b 37 days to orbit 51 Pegasi..

 Description 
51 Pegasi is a yellow dwarf star that is thought to be around 7.5 billion years old, which is somewhat older than our Sun. 51 Pegasi is also 4-6% more massive than our Sun with more metal content. However, it is running low on hydrogen.

The star itself has an apparent brightness of 5.49. Because of this, it can be seen from the Earth with binoculars, or with the naked eye if it is dark outside. 

The exoplanet's discovery was made public on October 6, 1995 by Michel Mayor and Didier Queloz.  The discovery was made using the radial velocity method at the Observatoire de Haute-Provence, using a tool called the ELODIE spectrograph that is used to find planets that are outside our Solar System. 

 Planetary system 

After the announcement, on October 12, 1995, more proof that this star did exist came from Dr. Geoffrey Marcy from San Francisco State University and Dr. R. Paul Butler from the University of California, Berkeley using the Hamilton Spectrograph at the Lick Observatory near San Jose in California.

51 Pegasi b is the first discovered planet of its parent star, 51 Pegasi. If any more are discovered they will be named 51 Pegasi c, 51 Pegasi d, and so on. The planet has been informally named Bellerophon. After its discovery, many teams proved its existence and continued to find out more about its properties, including the fact that it orbits very close to the star, has estimated temperatures around 1200 Celsius, and has a minimum mass about half of Jupiter's.

References

Other websites
 Extrasolar Visions: 51 Pegasi 
 51 Pegasi  at SolStation.com.
 nStars database entry 
 David Darling's encyclopedia

Category:Stars