144 citations · 1.1k across the 67 of their papers we have counts for
12 papers · 1 filter
Probable detection of an eruptive filament from a superflare on a solar-type star
Kosuke Namekata, Hiroyuki Maehara, Satoshi Honda +20
Solar flares are often accompanied by filament/prominence eruptions ( K and cm), sometimes leading to coronal mass ejections (CMEs) that direct…
Discovery of the Fastest Early Optical Emission from Overluminous SN Ia 2020hvf: A Thermonuclear Explosion within a Dense Circumstellar Environment
Ji-an Jiang, Keiichi Maeda, Miho Kawabata +28
In this Letter we report a discovery of a prominent flash of a peculiar overluminous Type Ia supernova, SN 2020hvf, in about 5 hours of the supernova explosion by the first wide-fi…
TOI-530b: A giant planet transiting an M dwarf detected by TESS
Tianjun Gan, Zitao Lin, Sharon Xuesong Wang +44
We report the discovery of TOI-530b, a transiting giant planet around an M0.5V dwarf, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located at a d…
TOI-2285b: A 1.7 Earth-radius Planet Near the Habitable Zone around a Nearby M Dwarf
Akihiko Fukui, Tadahiro Kimura, Teruyuki Hirano +60
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 days. We identified the transit signal from the Transitin…
Optical Variability Correlated with X-ray Spectral Transition in the Black-Hole Transient ASASSN-18ey = MAXI J1820+070
Keito Niijima, Mariko Kimura, Yasuyuki Wakamatsu +49
How a black hole accretes matter and how this process is regulated are fundamental but unsolved questions in astrophysics. In transient black-hole binaries, a lot of mass stored in…
Intermediate Luminosity Type Iax SN 2019muj With Narrow Absorption Lines: Long-Lasting Radiation Associated With a Possible Bound Remnant Predicted by the Weak Deflagration Model
Miho Kawabata, Keiichi Maeda, Masayuki Yamanaka +23
We present comprehensive spectroscopic and photometric analyses of the intermediate luminosity Type Iax supernova (SN Iax) 2019muj based on multi-band datasets observed through the…
TOI-1749: an M dwarf with a Trio of Planets including a Near-Resonant Pair
A. Fukui, J. Korth, J. H. Livingston +65
We report the discovery of one super-Earth- (TOI-1749b) and two sub-Neptune-sized planets (TOI-1749c and TOI-1749d) transiting an early M dwarf at a distance of 100~pc, which were…
On the nature of the anomalous event in 2021 in the dwarf nova SS Cygni and its multi-wavelength transition
Mariko Kimura, Shinya Yamada, Nozomi Nakaniwa +20
SS Cyg has long been recognized as the prototype of a group of dwarf novae that show only outbursts. However, this object has entered a quite anomalous event in 2021, which at firs…
BO Ceti: Dwarf Nova Showing Both IW And and SU UMa-Type Features
Taichi Kato, Yusuke Tampo, Naoto Kojiguchi +13
IW And stars are a recently recognized subgroup of dwarf novae which are characterized by (often repetitive) slowly rising standstills terminated by brightening, but the exact mech…
Spectroscopic and Photometric Observations of Dwarf Nova Superoutbursts by the 3.8 m Telescope Seimei and the Variable Star Network
Yusuke Tampo, Keisuke Isogai, Naoto Kojiguchi +59
We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at Okayama Observatory of Kyoto Un…
Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions
Teruyuki Hirano, John H. Livingston, Akihiko Fukui +58
We present observations of two bright M dwarfs (TOI-1634 and TOI-1685: ) hosting ultra-short period (USP) planets, identified by the TESS mission. The two stars are simi…
ASASSN-18aan: An Eclipsing SU UMa-type Cataclysmic Variable with a 3.6-hour Orbital Period and a Late G-type Secondary Star
Yasuyuki Wakamatsu, John R. Thorstensen, Naoto Kojiguchi +41
We report photometric and spectroscopic observations of the eclipsing SU UMa-type dwarf nova ASASSN-18aan. We observed the 2018 superoutburst with 2.3 mag brightening and found the…