8 papers
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. III. Comparison between Starspot Mapping, Zeeman Doppler Imaging, and Multiwavelength Variability
Kai Ikuta, Kosuke Namekata, Pascal Petit +12
Recent simultaneous multiwavelength observations of a nearby young solar-type star EK Dra in the optical, H spectrum, and X-ray, have provided evidence for stellar prominence e…
Superhumps and their Relation to the Disk Instability Model
Daisaku Nogami
Since the discovery of superhumps in 1974, these photometric modulations have provided a crucial observational window into disk instabilities in cataclysmic variable stars, particu…
Doppler imaging combined with high-cadence photometry. I. Revisiting the surface of a pre-main-sequence flare star
Sanghee Lee, Engin Bahar, Hakan Volkan Åenavcı +11
Latitude distribution of stellar magnetic activity is not well constrained by observations, despite its importance for a better understanding of stellar dynamos. We aim to obtain a…
Do Young Suns Produce Frequent, Massive CMEs? Results from Five-year Dedicated Optical Observations of EK Draconis and V889 Hercules
Kosuke Namekata, Hiroyuki Maehara, Yuta Notsu +4
We report results from a five-year (132-night) dedicated observational campaign targeting two nearby young solar-type stars, EK Draconis (50-125 Myr age) and V889 Hercules ($…
Time evolution of white-light flare accompanied by probable postflare loops on M-type dwarf EV Lacertae
Shinnosuke Ichihara, Daisaku Nogami, Kosuke Namekata +6
White-light flares are explosive phenomena accompanied by brightening of continuum from near-ultraviolet to optical, which occur on the Sun and stars. In order to investigate the m…
ASASSN-24hd; a dwarf nova bridging WZ Sge-type and SU UMa-type superoutbursts
Yusuke Tampo, Naoto Kojiguchi, Taichi Kato +9
WZ Sge-type dwarf novae (DNe) form a subclass in cataclysmic variables, characterized by short-period variations called superhumps during an outburst. Here we present optical groun…