Discovery | |
---|---|
Discovery site | Kepler telescope |
Discovery date | 2014 |
Transit | |
Orbital characteristics | |
1.219 AU (182,400,000 km) | |
704.1984 d | |
Inclination | 89.965 |
Star | Kepler-421 |
Physical characteristics | |
4.16 R🜨 | |
Kepler-421b is an exoplanet that, as of July 2014,[1] has the longest known year of any transiting planet (704 days),[2] although not as long as the planets that have been directly imaged, or many of the planets found by the radial-velocity method, or as long as some transiting planet candidates which are listed as planets in the Extrasolar Planets Encyclopaedia (KIC 5010054 b etc.).[3] It is the first transiting-planet found near the snow-line.
Normally, at least three transits are required to confirm a planet. Due to very high signal to noise ratio, only two transits were sufficient to validate Kepler-421b to be a real planet without additional confirmation methods.
Kepler-421b is slightly larger than Uranus although its mass is not known.