Discovery of a new IW And-type dwarf nova with both tilted disk and tidal instability

Fuente: arXiv
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Auteurs principaux: Sun, Yongkang, Li, Xin, Ao, Qige, Cui, Wenyuan, Zhang, Bowen, Huang, Yang, Shi, Jianrong, Li, Linlin, Liu, Jifeng
Format: Preprint
Publié: 2024
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author Sun, Yongkang
Li, Xin
Ao, Qige
Cui, Wenyuan
Zhang, Bowen
Huang, Yang
Shi, Jianrong
Li, Linlin
Liu, Jifeng
author_facet Sun, Yongkang
Li, Xin
Ao, Qige
Cui, Wenyuan
Zhang, Bowen
Huang, Yang
Shi, Jianrong
Li, Linlin
Liu, Jifeng
contents IW And-type dwarf novae are anomalous Z Cam stars featured with outbursts happening during standstill states, which are not expected in the standard disk instability model. The physical mechanisms for these variations remain unclear. In this study, we report the discovery of a new candidate IW And-type dwarf nova J0652+2436, identified with its frequent outbursts from the slowly rising standstill states. Luckily, the TESS observations during a long standstill state and the earlier K2 observations give a chance to find the orbital and negative superhump period in the light curve of J0652+2436, allowing the measurement of its mass ratio of 0.366. This mass ratio is marginally possible for the tidal instability to set in according to previous SPH simulations. Thus, we propose that the outbursts in J0652+2436 are likely to be caused by the growing accretion disk during standstills, in favor of the previous hypothesis of the mechanisms lying in all IW And stars. We conclude that J0652+2436 might be the first IW And star with both a precessing tilted disk and tidal instability, which will be an important laboratory for studying the accretion disk dynamics and help understand IW And phenomenon.
format Preprint
id arxiv_https___arxiv_org_abs_2404_09124
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Discovery of a new IW And-type dwarf nova with both tilted disk and tidal instability
Sun, Yongkang
Li, Xin
Ao, Qige
Cui, Wenyuan
Zhang, Bowen
Huang, Yang
Shi, Jianrong
Li, Linlin
Liu, Jifeng
Solar and Stellar Astrophysics
IW And-type dwarf novae are anomalous Z Cam stars featured with outbursts happening during standstill states, which are not expected in the standard disk instability model. The physical mechanisms for these variations remain unclear. In this study, we report the discovery of a new candidate IW And-type dwarf nova J0652+2436, identified with its frequent outbursts from the slowly rising standstill states. Luckily, the TESS observations during a long standstill state and the earlier K2 observations give a chance to find the orbital and negative superhump period in the light curve of J0652+2436, allowing the measurement of its mass ratio of 0.366. This mass ratio is marginally possible for the tidal instability to set in according to previous SPH simulations. Thus, we propose that the outbursts in J0652+2436 are likely to be caused by the growing accretion disk during standstills, in favor of the previous hypothesis of the mechanisms lying in all IW And stars. We conclude that J0652+2436 might be the first IW And star with both a precessing tilted disk and tidal instability, which will be an important laboratory for studying the accretion disk dynamics and help understand IW And phenomenon.
title Discovery of a new IW And-type dwarf nova with both tilted disk and tidal instability
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2404.09124