부산대학교 도서관

Transiting exoplanets orbiting young nearby stars are ideal laboratories for testing theories of planet formation and evolution. However, to date only a handful of stars with age <1 Gyr have been found to host transiting exoplanets. Here we present the discovery and validation of a sub-Neptune around HD 18599 , a young (300 Myr), nearby (d  = 40 pc) K star. We validate the transiting planet candidate as a bona fide planet using data from the TESS  , Spitzer  , and Gaia  missions, ground-based photometry from IRSF  , LCO  , PEST  , and NGTS  , speckle imaging from Gemini, and spectroscopy from CHIRON  , NRES  , FEROS  , and Minerva -Australis . The planet has an orbital period of 4.13 d , and a radius of 2.7 R ⊕ . The RV data yields a 3-σ mass upper limit of 30.5 M ⊕  which is explained by either a massive companion or the large observed jitter typical for a young star. The brightness of the host star (V ∼9 mag) makes it conducive to detailed characterization via Doppler mass measurement which will provide a rare view into the interior structure of young planets. [ABSTRACT FROM AUTHOR]