Superoutburst of WZSge-type dwarf nova below the period minimum: ASASSN-15po
Por:
Namekata, Kosuke, Isogai, Keisuke, Kato, Taichi, Littlefield, Colin, Matsumoto, Katsura, Kojiguchi, Naoto, Sugiura, Yuki, Uto, Yusuke, Fukushima, Daiki, Tatsumi, Taiki, Yamada, Eiji, Kamibetsunawa, Taku, de Miguel, Enrique, Stein, William L., Sabo, Richard, Andreev, Maksim V., Morelle, Etienne, Pavlenko, E. P., Babina, Julia V., Baklanov, Alex V., Antonyuk, Kirill A., Antonyuk, Okasana I., Sosnovskij, Aleksei A., Shugarov, Sergey Yu., Golysheva, Polina Yu., Gladilina, Natalia G., Miller, Ian, Neustroev, Vitaly V., Chavushyan, Vahram, Valdes, Jose R., Sjoberg, George, Maeda, Yutaka, Itoh, Hiroshi, Masi, Gianluca, Michel, Raul, Dubovsky, Pavol A., Kiyota, Seiichiro, Tordai, Tamas, Oksanen, Arto, Ruiz, Javier, Nogami, Daisaku
Publicada:
1 feb 2017
Resumen:
We report on a superoutburst of a WZ Sge-type dwarf nova (DN), ASASSN-15po. The light curve showed the main superoutburst and multiple rebrightenings. In this outburst, we observed early superhumps and growing (stage A) superhumps with periods of 0.050454(2) and 0.051809(13) d, respectively. We estimated that the mass ratio of secondary to primary (q) is 0.0699(8) by using Porb and a superhump period PSH of stage A. ASASSN-15po [Porb ~ 72.6 min] is the first DN with an orbital period between 67-76 min. Although the theoretical predicted period minimum Pmin of hydrogen-rich cataclysmic variables (CVs) is about 65-70 min, the observational cut-off of the orbital period distribution at 80 min implies that the period minimum is about 82min, and the value is widely accepted. We suggest the following four possibilities: the object is (1) a theoretical period minimum object, (2) a binary with a evolved secondary, (3) a binary with a metal-poor (Popullation II) seconday, or (4) a binary which was born with a brown-dwarf donor below the period minimum.
Filiaciones:
Namekata, Kosuke:
Kyoto Univ, Dept Astron, Sakyo Ku, Kitashirakawa Oiwake Cho, Kyoto, Kyoto 6068502, Japan
Isogai, Keisuke:
Kyoto Univ, Dept Astron, Sakyo Ku, Kitashirakawa Oiwake Cho, Kyoto, Kyoto 6068502, Japan
Kato, Taichi:
Kyoto Univ, Dept Astron, Sakyo Ku, Kitashirakawa Oiwake Cho, Kyoto, Kyoto 6068502, Japan
Littlefield, Colin:
Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
Matsumoto, Katsura:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Kojiguchi, Naoto:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Sugiura, Yuki:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Uto, Yusuke:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Fukushima, Daiki:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Tatsumi, Taiki:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Yamada, Eiji:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
Kamibetsunawa, Taku:
Osaka Kyoiku Univ, 4-698-1 Asahigaoka, Osaka 5828582, Japan
de Miguel, Enrique:
Univ Huelva, Fac Ciencias Expt, Dept Fis Aplicada, Huelva 21071, Spain
Ctr Backyard Astrophys, Observ CIECEM, Parque Dunar, Almonte 21760, Huelva, Spain
Stein, William L.:
66025 Calle Paraiso, Las Cruces, NM 88012 USA
Sabo, Richard:
72336 Trailcrest Dr, Bozeman, MT 59718 USA
Andreev, Maksim V.:
Russian Acad Sci, Terskol Branch Inst Astron, Peak Terskol 361605, Kabardino Balka, Russia
NASU, Int Ctr Astron Med & Ecol Res, Ukraine 27 Akad Zabolotnoho Str, UA-03680 Kiev, Ukraine
Morelle, Etienne:
9 Rue Vasco GAMA, F-59553 Lauwin Planque, France
Pavlenko, E. P.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Babina, Julia V.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Baklanov, Alex V.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Antonyuk, Kirill A.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Antonyuk, Okasana I.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Sosnovskij, Aleksei A.:
Crimean Astrophys Observ, UA-298409 Nauchnyi, Crimea, Ukraine
Shugarov, Sergey Yu.:
Lomonosov Moscow Univ, Sternberg Astron Inst, Univ Skaya Ave 13, Moscow 119992, Russia
Slovak Acad Sci, Astron Inst, Tatranska Lomnica 05960, Slovakia
Golysheva, Polina Yu.:
Lomonosov Moscow Univ, Sternberg Astron Inst, Univ Skaya Ave 13, Moscow 119992, Russia
Gladilina, Natalia G.:
Russian Acad Sci, Inst Astron, 119017 Pyatnitskaya Str 48, Moscow, Russia
Miller, Ian:
Furzehill House, Swansea SA2 7LE, W Glam, Wales
Neustroev, Vitaly V.:
Univ Oulu, Astron Res Unit, POB 3000, FIN-90014 Oulu, Finland
Univ Turku, Finnish Ctr Astron ESO FINCA, Vaisalnite 20, FIN-21500 Piikkio, Finland
Chavushyan, Vahram:
Inst Nacl Astrofis Opt & Electr, Luis Enrique Erro 1, Puebla 72840, Mexico
Valdes, Jose R.:
Inst Nacl Astrofis Opt & Electr, Luis Enrique Erro 1, Puebla 72840, Mexico
Sjoberg, George:
Amer Assosicat Variable Star Observers, 49 Bay State Rd, Cambridge, MA 02138 USA
George Elma Observ, Mayhill, NM USA
Maeda, Yutaka:
Kaminishiyamamachi 12-14, Nagasaki, Nagasaki 8500006, Japan
Itoh, Hiroshi:
VSOLJ, 1001-105 Nishiterakata, Hachioji, Tokyo 1920153, Japan
Masi, Gianluca:
Virtual Telescope Project, Via Madonna Loco 47, I-03023 Ceccano, FR, Italy
Michel, Raul:
UNAM, Inst Astron, Apartado Postal 877, Ensenada 22800, Baja California, Mexico
Dubovsky, Pavol A.:
Vihorlat Observ, Mierova 4, Humenne, Slovakia
Kiyota, Seiichiro:
VSOLJ, 7-1 Kitahatsutomi, Kamagaya, Chiba 2730126, Japan
Tordai, Tamas:
Hungarian Astron Assoc, Polaris Observ, Laborc 2-c, H-1037 Budapest, Hungary
Oksanen, Arto:
Jyvaskylan Sirius Ry, Hankasalmi Observ, Verkkoniementie 30, Muurame 40950, Finland
Ruiz, Javier:
Observ Cantabria, Ctra Rocamundo S-N, Valderredible 39220, Cantabria, Spain
CSIC, Inst Fis Cantabria, UC, Ave Castros S-N, E-39005 Santander, Cantabria, Spain
Agrupac Astron Cantabria, Apartado 573, Santander 39080, Spain
Nogami, Daisaku:
Kyoto Univ, Dept Astron, Sakyo Ku, Kitashirakawa Oiwake Cho, Kyoto, Kyoto 6068502, Japan
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