Starspot mapping and multiwavelength variability for a young solar-type star

Recent simultaneous multiwavelength observations by the TESS, Seimei telescope, and NICER have provided evidence for stellar prominence eruptions associated with superflares on a young solar-type star EK Draconis (EK Dra) (Namekata et al. 2024). Such superflares are suggested to have been caused by large spots near the limb from the concurrent result of the Doppler Imaging at the Bernard Lyot telescope (Namekata et al., to be submitted). Thus, to investigate the relation between spot locations from the optical photometry and occurrence of superflares, we perform starspot mapping for the TESS light curve of EK Dra. We also analyze the rotational variability for the TESS light curve, Hα spectrum, and X-ray data. As a result, we find that (i) some spots are deduced to be near the limb when superflares occurred, (ii) spot locations are consistent with those obtained from the Doppler Imaging except for a polar spot, and (iii) the Hα spectrum produced around spots exhibits clear periodicity with respect to the TESS light curve, however, the X-ray data does not show such association probably because of multiple spots on the surface and the extended spatial structure of coronal active regions (Ikuta et al., in preparation).