We announce the detection of recurring sets of recurring starspot occultation events in the short-cadence K2 lightcurve of Qatar-2, a K dwarf star transited every 1.34 d by a hot Jupiter. In total we detect 34 individual starspot occultation events, caused by five different starspots, occulted in up to five consecutive transits or after a full stellar rotation. The longest recurring set of recurring starspot occultations spans over three stellar rotations, setting a lower limit for the longest starspot lifetime of 58 d. Starspot analysis provided a robust stellar rotational period measurement of $18.0\pm0.2$ d and indicates that the system is aligned, having a sky-projected obliquity of $0\pm8^{\circ}$. A pronounced rotational modulation in the lightcurve has a period of $18.2\pm1.6$ d, in agreement with the rotational period derived from the starspot occultations. We tentatively detect an ellipsoidal modulation in the phase-curve, with a semi-amplitude of 18 ppm, but cannot exclude the possibility that this is the result of red noise or imperfect removal of the rotational modulation. We detect no transit-timing and transit-duration variations with upper limits of 15 s and 1 min, respectively. We also reject any additional transiting planets with transit depths above 280 ppm in the orbital period region 0.5-30 d.
KRONOS II: Solar-like Umbra and Penumbra Properties on the Young Sun V1298~Tau
Michigan State University（密歇根州立大学）；Massachusetts Institute of Technology（麻省理工学院）；Arizona State University（亚利桑那州立大学）；Vanderbilt University（范德堡大学）；Max Planck Institute for Astronomy (MPIA)（马克斯·普朗克天文学研究所）；National Astronomical Observatory of Japan（日本国立天文台）
利用 JWST NIRISS/SOSS 掩星观测年轻行星 V1298 Tau bcd，通过星食事件光谱分析，发现宿主星 V1298~Tau 的黑子具有类似太阳的本影和半影结构，温度分别为 3265-3436 K 和 4388-4659 K，且本影面积占比约 30%。
