Changes

==Planets==

==Planets==

51 Pegasi was the star where the first extrasolar world was discovered using radial-velocity methods; astronomers Michel mayor and Didier Queloz announced the discovery the Jupiter class gas giant on October 12, 1995<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995Natur.378..355M&db_key=AST&high=3b4b5e274020634</ref>.  Independent confirmation of the world came from [[San Francisco State University]], [[University of California]], and the Lick Observatory.  The world is nicknamed "Bellerophon"<ref>http://jumk.de/astronomie/exoplanets/51-pegasi.shtml</ref>.

51 Pegasi was the star where the first extrasolar world was discovered using radial-velocity methods; astronomers Michel Mayor and Didier Queloz announced the discovery the Jupiter class gas giant on October 12, 1995<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995Natur.378..355M&db_key=AST&high=3b4b5e274020634</ref>.  Independent confirmation of the world came from [[San Francisco State University]], [[University of California]], and the Lick Observatory.  The world is nicknamed "Bellerophon", although its official astronomical designation is ''51 Pegasi b''.<ref>http://jumk.de/astronomie/exoplanets/51-pegasi.shtml</ref>.

The world has at least 46 percent of [[Jupiter|Jupiter’s]] mass and maintains a very close orbit of 0.052 AUs from its parent star.  Because of how close the planet is to 51 Pegasi, its orbit only takes 4.2 days.  Because of this distance, the world is tidally locked.  Temperatures are estimated to be 1265K (around 1000 degrees Celsius / 1800 degrees Fahrenheit) on average.   

The planet itself has at least 46 percent of [[Jupiter|Jupiter’s]] mass and maintains a very close orbit of 0.052 AUs from its parent star.  Because of how close the planet is to 51 Pegasi, its orbit only takes 4.2 days to complete.  Because of this distance, the world is tidally locked to its parent star.  Temperatures are estimated to be 1265K (around 1000 degrees Celsius / 1800 degrees Fahrenheit) on average.   

The world is also remarkable because a world so close to its parent star was not compatible with planet formation theories at the time, and the world was considered an anomaly.  Since then other such “hot Jupiters” have been discovered challenging astronomers to revise the theories of planetary formation, one way is by studying orbit migration.

The world is also remarkable because a world so close to its parent star was not compatible with planet formation theories at the time, and the planet was considered an anomaly.  Since then other such “hot Jupiters” have been discovered challenging astronomers to revise the theories of planetary formation, one way is by studying orbit migration.

A terrestrial planet that could maintain liquid water on its surface could hypothetically exist in a [[habitable zone]] that ranges from 1.2 AU to 2.0 AUs away for 51 Pegasi<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001AAS...199.0310N&db_key=AST&high=3cab10bb0312474</ref>.  The star is a target for NASA’s Terrestrial Planet Finder (TPF) and the ESA's Darwin in the future.   

A [[terrestrial planet]] that could maintain liquid water on its surface could hypothetically exist in a [[habitable zone]] that ranges from 1.2 AU to 2.0 AUs away for 51 Pegasi<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001AAS...199.0310N&db_key=AST&high=3cab10bb0312474</ref>.  The star is a target for NASA’s Terrestrial Planet Finder (TPF) and the ESA's Darwin in the future.   

No other worlds are known at this time.

No other worlds are known at this time.