We report the discovery by the ground-based Hungarian-made Automated
Telescope Network (HATNet) survey of the transiting exoplanet HAT-P-68b,
which has a mass of 0.724 ± 0.043 M J, and radius of 1.072 ± 0.012 R J. The planet is in a circular P = 2.2984 day orbit around a moderately bright V = 13.937 ± 0.030 magnitude K-dwarf star of mass M ⊙, and radius 0.6726 ± 0.0069 R ⊙.
The planetary nature of this system is confirmed through follow-up
transit photometry obtained with the Fred L. Whipple Observatory
(FLWO) 1.2 m telescope, high-precision radial velocities measured using
Keck I/High Resolution Echelle Spectrometer (HIRES), FLWO 1.5
m/Tillinghast Reflector Echelle Spectrograph (TRES), and Observatoire de
Haute-Provence (OHP) 1.9 m/Sophie, and high-spatial-resolution speckle
imaging from WIYN 3.5 m/DSSI. HAT-P-68 is at an ecliptic latitude of +3°
and outside the field of view of both the NASA Transiting Exoplanet
Survey Satellite primary mission and the K2 mission. The large transit
depth of 0.036 mag (r band) makes HAT-P-68b a promising target for atmospheric characterization via transmission spectroscopy.