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Errai A b, Gamma Cephei A b, HD 222404 b

Proper NamesTadmor, Errai b, Errai A b
DesignationsGamma Cephei (A) b, HD 222404 (A) b
ClassificationGas Giant
Orbital Period905 days
Mean Distance from Errai A290 million km
1.94 AU
Mass9.4 x Jupiter
DiameterNot known
TemperatureNot known
Parent starErrai, orange giant in Cepheus
Other planets in this systemNone
NotesIn 1988, this was the first planet outside the Solar System whose existence was at least suspected, although questions over its original discovery data meant that it was not formally confirmed until 2002. It is now known to be an immense gas giant with a mass estimated at nearly ten times that of Jupiter.


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