Kepler-34b

Kepler-34b (formally Kepler-34(AB)b) is a circumbinary planet announced with Kepler-35b. It is a small gas giant that orbits every ~288 days around two stars. Despite the planet's relatively long orbital period, its existence could be confirmed quickly due to transiting both of its host stars.

Kepler-34b

Discovery
Discovery date	01-11-2012
Detection method	Transit (Kepler Mission)
Orbital characteristics
Epoch BJD 2454969.2000
Semi-major axis	1.0896 ± 0.0009 AU (163,000,000 ± 130,000 km)
Eccentricity	0.182 +0.0016 −0.0020
Orbital period (sidereal)	288.822 +0.063 −0.081 d
Inclination	90.355 +0.026 −0.018
Longitude of ascending node	−1.74 +0.14 −0.16
Longitude of periastron	106.5 +2.5 −2.0
Star	Kepler-34
Physical characteristics
Mean radius	0.764 +0.0012 −0.0014 RJ 8.56 R🜨
Mass	0.220 +0.011 −0.010 MJ (69.9 ME)
Mean density	0.613 +0.045 −0.041 g cm−3
Surface gravity	936 +57 −54 m/s²
Temperature	323

Kepler-34b was unlikely to form at its current orbit, and likely migrated early from its birth orbit beyond 1.5 AU away from its parent binary stars, suffering multiple giant impacts in the process.^[1] The eccentricity of its planetary orbit might have been acquired on the last stage of migration, due to interaction with the residual debris disk,^[2] or by ejection of a second planet.^[3]