A study of the long-term activity of five intermediate polars with accretion discs
A study of the long-term activity of five intermediate polars with accretion discs
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DOI：
10.1093/mnras/stab739
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发表时间：
2021-05
影响因子：
4.8
通讯作者：
V. Šimon
中科院分区：
文献类型：
--
作者：
V. Šimon
中间极(IP)是具有轻度磁化的白矮星(WD)的激变变星。这项对五个具有吸积盘的IP的长期光学活动的分析使用了来自Catalina实时瞬变调查、数字接入天空世纪@哈佛(DASCH)和美国变星观察者协会(AAVSO)的数据。结果表明，尽管在超轨道时间尺度上有很大的变化，但每个IP都有其最喜欢的绝对星等MOPT的值。这些IP的MOPT值大部分时间都在椎间盘的热-粘性不稳定性(TVI)区域。V426Oph的一系列爆发特性可以用间歇运行的TVI来解释。TV Col和DW Cnc的活动被解释为从辅助盘到冷却盘的质量流入速率逐渐变化造成的。二次传质速率在确定的时间尺度上变化很大。结果表明，Ei Uma的MOPT在接近非磁性矮新星爆发峰值的时间尺度上存在天数起伏，它还产生了短耀斑，这归因于施主物质的爆发。Hy Leo，大概有一个很酷的圆盘，在它的高和低状态之间波动。从延长的低状态暂时变亮被归因于从施主到剩余的冷盘或环的短暂而强烈的物质爆发。
Intermediate polars (IPs) are cataclysmic variables with mildly magnetized white dwarfs (WDs). This analysis of the long-term optical activity of five examples of IPs with accretion discs used data from the Catalina Real-time Transient Survey, Digital Access to a Sky Century @ Harvard (DASCH) and the American Association of Variable Star Observers (AAVSO). It is shown that each of these IPs had their most preferred value of absolute magnitude Mopt, even if it significantly varied on the superorbital time-scale. The values of Mopt of these IPs were in the zone of thermal-viscous instability (TVI) of the disc most of the time. The properties of a series of outbursts of V426 Oph can be explained by an intermittently operating TVI. The activity of TV Col and DW Cnc is interpreted as caused by a gradually variable mass inflow rate from the secondary to a cool disc. The mass transfer rate from the secondary varied on a well-determined time-scale. It is shown that Mopt of EI UMa, close to the peaks of outbursts of non-magnetic dwarf novae, fluctuated on the time-scale of days; it also produced short flares, ascribed to the bursts of matter from the donor. HY Leo, with a presumably cool disc, fluctuated between its high and low states. A temporary brightening from an extended low state is ascribed to a short, intense burst of matter from the donor to the remaining cool disc or torus.