We report the discovery of two planets transiting the bright stars HD 89345
(EPIC 248777106, V=9.376, K=7.721) in K2 Campaign 14 and HD 286123 (EPIC
247098361, V=9.822, K=8.434) in K2 Campaign 13. Both stars are G-type
stars, one of which is at or near the end of its main sequence lifetime, and
the other that is just over halfway through its main sequence lifetime. HD
89345 hosts a warm sub-Saturn (0.66 RJ, 0.11 MJ, Teq=1100 K)
in an 11.81-day orbit. The planet is similar in size to WASP-107b, which falls
in the transition region between ice giants and gas giants. HD 286123 hosts a
Jupiter-sized, low-mass planet (1.06 RJ, 0.39 MJ, Teq=1000 K)
in an 11.17-day, mildly eccentric orbit, with e=0.255±0.035. Given that
they orbit relatively evolved main-sequence stars and have orbital periods
longer than 10 days, these planets are interesting candidates for studies of
gas planet evolution, migration, and (potentially) re-inflation. Both planets
have spent their entire lifetimes near the proposed stellar irradiation
threshold at which giant planets become inflated, and neither shows any sign of
radius inflation. They probe the regime where inflation begins to become
noticeable and are valuable in constraining planet inflation models. In
addition, the brightness of the host stars, combined with large atmospheric
scale heights of the planets, makes these two systems favorable targets for
transit spectroscopy to study their atmospheres and perhaps provide insight
into the physical mechanisms that lead to inflated hot Jupiters.Comment: 16 pages, 12 figures; accepted for publication in A