Kepler-730 is a planetary system hosting a statistically validated hot Jupiter in a 6.49 day orbit and an additional transiting candidate in a 2.85 day orbit .
We use spectroscopic radial velocities from the APOGEE-2N instrument , Robo-AO contrast curves , and Gaia distance estimates to statistically validate the planetary nature of the additional Earth-sized candidate .
We perform astrophysical false positive probability calculations for the candidate using the available Kepler data and bolster the statistical validation using radial velocity data to exclude a family of possible binary star solutions .
Using a radius estimate for the primary star derived from stellar models , we compute radii of 1.100 ^ { +0.047 } _ { -0.050 } \mathrm { R _ { Jup } } and 0.140 \pm 0.012 \mathrm { R _ { Jup } } ( 1.57 \pm 0.13 \mathrm { R _ { \oplus } } ) for Kepler-730b and Kepler-730c , respectively .
Kepler-730 is only the second compact system hosting a hot Jupiter with an inner , transiting planet .