摘要：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 is justover halfway through its main-sequence lifetime. HD 89345 hosts a warm sub-Saturn (0.66 R J , 0.11 M J ,T eq =1100 K) in an 11.81 day orbit. The planet is similar in size to WASP-107b, which falls in the transitionregion between ice giants and gas giants. HD 286123 hosts a Jupiter-sized, low-mass planet (1.06 R J , 0.39 M J ,T eq =1000 K) in an 11.17 day, mildly eccentric orbit, with e=0.255±0.035. Given that they orbit relativelyevolved main-sequence stars and have orbital periods longer than 10 days, these planets are interesting candidatesfor studies of gas planet evolution, migration, and (potentially) reinflation. Both planets have spent their entirelifetimes near the proposed stellar irradiation threshold at which giant planets become inflated, and neither showsany sign of radius inflation. They probe the regime where inflation begins to become noticeable and are valuable inconstraining planet inflation models. In addition, the brightness of the host stars, combined with large atmosphericscale heights of the planets, makes these two systems favorable targets for transit spectroscopy to study theiratmospheres and perhaps provide insight into the physical mechanisms that lead to inflated hot Jupiters.
关键词：planetary systems;stars: individual (HD 89345, HD 286123);techniques: photometric;techniques: spectroscopic
