Zobrazeno 1 - 10
of 178
pro vyhledávání: '"Daisaku Nogami"'
Autor:
Yuta Notsu, Adam F. Kowalski, Hiroyuki Maehara, Kosuke Namekata, Kenji Hamaguchi, Teruaki Enoto, Isaiah I. Tristan, Suzanne L. Hawley, James R. A. Davenport, Satoshi Honda, Kai Ikuta, Shun Inoue, Keiichi Namizaki, Daisaku Nogami, Kazunari Shibata
Publikováno v:
The Astrophysical Journal, Vol 961, Iss 2, p 189 (2024)
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate
Externí odkaz:
https://doaj.org/article/f5c6d27694c84a49bf8bb9ee21fe127c
Autor:
Kenta Taguchi, Keiichi Maeda, Hiroyuki Maehara, Akito Tajitsu, Masayuki Yamanaka, Akira Arai, Keisuke Isogai, Masaaki Shibata, Yusuke Tampo, Naoto Kojiguchi, Daisaku Nogami, Taichi Kato
Publikováno v:
The Astrophysical Journal, Vol 958, Iss 2, p 156 (2023)
The lowest possible mass of ONeMg white dwarfs (WDs) has not been clarified despite its importance in the formation and evolution of WDs. We tackle this issue by studying the properties of V1405 Cas (Nova Cassiopeiae 2021), which is an outlier given
Externí odkaz:
https://doaj.org/article/b7b7fa0f906d43d28c949547db897fa8
Autor:
Kai Ikuta, Kosuke Namekata, Yuta Notsu, Hiroyuki Maehara, Soshi Okamoto, Satoshi Honda, Daisaku Nogami, Kazunari Shibata
Publikováno v:
The Astrophysical Journal, Vol 948, Iss 1, p 64 (2023)
Starspots and stellar flares are indicators of stellar magnetic activity. The magnetic energy stored around spots is thought to be the origin of flares, but the connection is not completely understood. To investigate the relation between spot locatio
Externí odkaz:
https://doaj.org/article/8353a31bf3e54a8e9d59f517b32f0ac9
Autor:
Shun Inoue, Hiroyuki Maehara, Yuta Notsu, Kosuke Namekata, Satoshi Honda, Keiichi Namizaki, Daisaku Nogami, Kazunari Shibata
Publikováno v:
The Astrophysical Journal, Vol 948, Iss 1, p 9 (2023)
Stellar coronal mass ejections (CMEs) have recently received much attention for their impacts on exoplanets and stellar evolution. Detecting prominence eruptions, the initial phase of CMEs, as the blueshifted excess component of Balmer lines is a tec
Externí odkaz:
https://doaj.org/article/111d0966a0f84e22a1fedb9084c0c765
Autor:
Keiichi Namizaki, Kosuke Namekata, Hiroyuki Maehara, Yuta Notsu, Satoshi Honda, Daisaku Nogami, Kazunari Shibata
Publikováno v:
The Astrophysical Journal, Vol 945, Iss 1, p 61 (2023)
Active M-type stars are known to often produce superflares on the surface. Radiation from stellar (super)flares is important for exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical spectro
Externí odkaz:
https://doaj.org/article/02671677cf674e30abb4a573b63d80c1
Autor:
Takashi Horiuchi, Hidekazu Hanayama, Masatoshi Ohishi, Tatsuya Nakaoka, Ryo Imazawa, Koji S Kawabata, Jun Takahashi, Hiroki Onozato, Tomoki Saito, Masayuki Yamanaka, Daisaku Nogami, Yusuke Tampo, Naoto Kojiguchi, Jumpei Ito, Masaaki Shibata, Malte Schramm, Yumiko Oasa, Takahiro Kanai, Kohei Oide, Katsuhiro L Murata, Ryohei Hosokawa, Yutaka Takamatsu, Yuri Imai, Naohiro Ito, Masafumi Niwano, Seiko Takagi, Tatsuharu Ono, Vladimir V Kouprianov
Publikováno v:
Publications of the Astronomical Society of Japan.
This study provides the results of simultaneous multicolor observations for the first Visorsat (STARLINK-1436) and the ordinary Starlink satellite, STARLINK-1113 in the $U$, $B$, $V$, $g'$, $r$, $i$, $R_{\rm C}$, $I_{\rm C}$, $z$, $J$, $H$, and $K_s$
Autor:
Yusuke Tampo, Taichi Kato, Naoto Kojiguchi, Sergey Yu Shugarov, Hiroshi Itoh, Katsura Matsumoto, Momoka Nakagawa, Yukitaka Nishida, Michael Richmond, Masaaki Shibata, Junpei Ito, Gulchehra Kokhirova, Firuza Rakhmatullaeva, Tamás Tordai, Seiichiro Kiyota, Javier Ruiz, Pavol A Dubovsky, Tomáš Medulka, Elena P Pavlenko, Oksana I Antonyuk, Aleksei A Sosnovskij, Aleksei V Baklanov, Viktoriia Krushevska, Tonny Vanmunster, Stephen M Brincat, Karol Petrik, Charles Galdies, Franz-Josef Hambsch, Yutaka Maeda, Daisaku Nogami
Superoutbursts in WZ Sge-type dwarf novae (DNe) are characterized by both early superhumps and ordinary superhumps originating from the 2:1 and 3:1 resonances, respectively. However, some WZ Sge-type DNe show a superoutburst lacking early superhumps;
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1465452de8547391e83e176ba1635277
http://arxiv.org/abs/2303.17960
http://arxiv.org/abs/2303.17960
Autor:
Keiichi Namizaki, Kosuke Namekata, Hiroyuki Maehara, Yuta Notsu, Satoshi Honda, Daisaku Nogami, Kazunari Shibata
Active M-type stars are known to often produce superflares on the surface. Radiation from stellar (super-)flares is important for the exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical sp
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::531f158ecb5488bf8aaa86a52d954739
http://arxiv.org/abs/2302.03007
http://arxiv.org/abs/2302.03007
Autor:
Kosuke Namekata, Hiroyuki Maehara, Satoshi Honda, Yuta Notsu, Soshi Okamoto, Jun Takahashi, Masaki Takayama, Tomohito Ohshima, Tomoki Saito, Noriyuki Katoh, Miyako Tozuka, Katsuhiro L. Murata, Futa Ogawa, Masafumi Niwano, Ryo Adachi, Motoki Oeda, Kazuki Shiraishi, Keisuke Isogai, Daikichi Seki, Takako T. Ishii, Kiyoshi Ichimoto, Daisaku Nogami, Kazunari Shibata
Publikováno v:
Nature Astronomy. 6:241-248
Solar flares are often accompanied by filament/prominence eruptions (~10⁴ K and ~10¹⁰⁻¹¹ cm⁻³), sometimes leading to coronal mass ejections that directly affect the Earth’s environment. ‘Superflares’ are found on some active solar-t
Autor:
S. Kafka, Tom Marsh, Arto Oksanen, Diogo Belloni, Daisaku Nogami, M. J. Cook, Peter Nelson, Roger D. Pickard, Dean M. Townsley, Edward M. Sion, Elmé Breedt, Christian Knigge, Daniel E. Reichart, Rod Stubbings, Matthias R. Schreiber, Vladimir Kouprianov, Boris T. Gänsicke, Patrick Godon, Paula Szkody, Odette Toloza, Berto Monard, Jeremy Shears, D. de Martino, Lars Bildsten, Gary Poyner, Steven G. Parsons, D. Rodriguez Perez, David Boyd, Knox S. Long, A. F. Pala, Gordon Myers
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 510:6110-6132
We report on the masses ($M_\mathrm{WD}$), effective temperatures ($T_\mathrm{eff}$) and secular mean accretion rates ($\langle \dot{M} \rangle$) of 43 cataclysmic variable (CV) white dwarfs, 42 of which were obtained from the combined analysis of th