We report the discovery of two transiting extrasolar planets by the HATSouth survey .
HATS-9b orbits an old ( 10.8 \pm 1.5 Gyr ) V=13.3 G dwarf star , with a period P \approx 1.9153 d. The host star has a mass of 1.03 M _ { \sun } , radius of 1.503 R _ { \sun } and effective temperature 5366 \pm 70 K. The planetary companion has a mass of 0.837 M _ { J } , and radius of 1.065 R _ { J } yielding a mean density of 0.85 g cm ^ { -3 } .
HATS-10b orbits a V=13.1 G dwarf star , with a period P \approx 3.3128 d. The host star has a mass of 1.1 M _ { \sun } , radius of 1.11 R _ { \sun } and effective temperature 5880 \pm 120 K. The planetary companion has a mass of 0.53 M _ { J } , and radius of 0.97 R _ { J } yielding a mean density of 0.7 g cm ^ { -3 } .
Both planets are compact in comparison with planets receiving similar irradiation from their host stars , and lie in the nominal coordinates of Field 7 of K2 but only HATS-9b falls on working silicon .
Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature .