论文标题
V476 CYG（Nova Cyg 1920）目前是Nova - 首先是当时差距中的对象？
V476 Cyg (Nova Cyg 1920) is currently a dwarf nova -- first such an object in the period gap?
论文作者
论文摘要
V476 CYG（Nova Cyg 1920）是一个明亮，快速的NOVA，其摄影幅度为2.0。使用Zwicky瞬态设施（ZTF）公共数据库，我发现这个Nova目前是一个矮人Nova，周期长度约为24 d。与目前在矮新星型州的其他古典Novae相比，V476 CYG的爆发迅速上升，并且持续了几天。根据AAVSO的观察，这个Nova可能已经在Nova爆发96年的2016年矮人Nova型阶段处于矮人。我发现使用ZTF数据可能会将对象置于周期间隙中的0.1018002（6）d的轨道周期。这个所谓的短轨道时期似乎解释了观察到的矮人爆发的特征和微弱的绝对幅度。如果确认了这一时期，V476 CYG是一个经典的Nova，其轨道时期最短，矮小的Nova爆发，并且在现代记录了Nova爆发。我还与V446 HE（Nova她的1960年）进行了比较，目前显示了SS Cyg型爆发。 V476 CYG中向矮人Nova期的过渡发生的时间要早（〜100岁），比在周期间隙以下的经典Novae所谓的（〜1000年）。 V476 CYG不仅可以为预期潮汐不稳定的辐照吸积盘的行为提供理想的实验室，而且还可以为大型白矮星对矮人Nova爆发的影响提供了理想的实验室。
V476 Cyg (Nova Cyg 1920) is a bright, fast nova reaching a photographic magnitude of 2.0. Using the Zwicky Transient Facility (ZTF) public database, I found that this nova is currently a dwarf nova with a cycle length of ~24 d. Compared to other classical novae currently in dwarf nova-type states, outbursts of V476 Cyg are rapidly rising and short with durations of a few days. Based on the AAVSO observations, this nova was probably already in the dwarf nova-type phase in 2016, 96 years after the nova eruption. I found a possible orbital period of 0.1018002(6) d using the ZTF data, which would place the object in the period gap. This supposed short orbital period appears to explain the features and faint absolute magnitudes of the observed dwarf nova outbursts. If this period is confirmed, V476 Cyg is a classical nova with the shortest orbital period with distinct dwarf nova outbursts and in which a nova eruption was recorded in the modern era. I also compared with the outburst properties with V446 Her (Nova Her 1960), which currently shows SS Cyg-type outbursts. The transition to the dwarf nova-phase in V476 Cyg occurred much earlier (~100 yr) than what has been supposed (~1000 yr) for classical novae below the period gap. V476 Cyg would not only provide an ideal laboratory of the behavior of an irradiated accretion disk in which tidal instability is expected to work, but also an ideal laboratory of the effect of a massive white dwarf on dwarf nova outbursts.
