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Helvetios b, 51 Pegasi b, ‘Bellerophon’

Proper NamesDimidium; originally provisionally named ‘Bellerophon’
Designation51 Pegasi b
ClassificationGas Giant
Orbital Period4.23 days
Mean Distance from Helvetios7 million km
0.05 AU
Mass0.46 x Jupiter
Diameter> 1.6 x Jupiter
Temperature1,260 K (990°C)
Parent starHelvetios (51 Pegasi), yellow subgiant in Pegasus
Other planets in this systemNone
NotesNotable as the first extrasolar planet to be discovered in orbit of a typical star (second only to a planetary system found around the pulsar now known as Lich), Dimidium takes its name (meaning 'half') from its mass, which is a little under half that of Jupiter.

The designation given to the large world thought to orbit Helvetios or 51 Pegasi, a yellow star fifty light years away from Earth's solar system.

Imagery provided by Aladin sky atlas


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