IW And-type state in IM Eridani

Abstract IW And stars are a recently recognized group of dwarf novae which are characterized by a repeated sequence of brightening from a standstill-like phase with damping oscillations followed by a deep dip. Kimura et al. (2019, PASJ, submitted) recently proposed a model based on thermal-viscous d...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Publications of the Astronomical Society of Japan 2020-02, Vol.72 (1), Article 11
Hauptverfasser: Kato, Taichi, Wakamatsu, Yasuyuki, Kojiguchi, Naoto, Kimura, Mariko, Ohnishi, Ryuhei, Isogai, Keisuke, Niijima, Keito, Yoshitake, Tomohiro, Sugiura, Yuki, Sumiya, Sho, Ito, Daiki, Nikai, Kengo, Matsumoto, Hanami, Matsumoto, Katsura, Vanmunster, Tonny, Hambsch, Franz-Josef, Itoh, Hiroshi, Babina, Julia V, Antonyuk, Oksana I, Baklanov, Alex V, Pavlenko, Elena P, Monard, Berto, Dvorak, Shawn
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Abstract IW And stars are a recently recognized group of dwarf novae which are characterized by a repeated sequence of brightening from a standstill-like phase with damping oscillations followed by a deep dip. Kimura et al. (2019, PASJ, submitted) recently proposed a model based on thermal-viscous disk instability in a tilted disk to reproduce the IW And-type characteristics. IM Eri experienced the IW And-type phase in 2018 and we recorded three cycles of the (damping) oscillation phase terminated by brightening. We identified two periods during the IW And-type state: 4–5 d small-amplitude (often damping) oscillations and a 34–43 d long cycle. This behavior is typical for an IW And-type star. The object gradually brightened within the long cycle before the next brightening, which terminated the (damping) oscillation phase. This observation agrees with the increasing disk mass during the long cycle predicted by the Kimura et al. model of thermal-viscous disk instability in a tilted disk. We did not, however, succeed in detecting negative superhumps, which are considered to be the signature of a tilted disk.
ISSN:0004-6264
2053-051X
DOI:10.1093/pasj/psz130