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arXiv 2009.11902astro-ph.SR
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T CrB的活动增加表明新星喷发即将发生

Increasing activity in T CrB suggests nova eruption is impending

Gerardo J. M. Luna, J. L. Sokoloski, K. Mukai, P. Kuin

摘要:

共生复发新星(RNe)的吸积率的估计往往达不到理论预期的数量级。如果白矮星(WD)的质量积累是高度分散的,并且大多数观测都是在低状态下进行的,那么这种明显的差异就可以解决。在这里,我们使用的档案数据的重新分析,从数字访问天空世纪@哈佛大学(DASCH)调查认为,最近的新星喷发共生RN T CrB,在1946年,发生在-因此触发-一个短暂的吸积高状态。基于相似的光学光变曲线在1946年左右的前一次喷发的时间,在1866年,我们认为WD在T CrB积累的大部分燃料需要点燃热核失控(TNR)在吸积高状态。这种状态的一个自然起源是类似于矮新星的吸积盘不稳定性,这是在共生双星中可能存在的大圆盘中预期的。因此,共生RNe中TNR的时间可以由它们的吸积盘的稳定性来决定。T CrB正处于吸积的高状态,就像我们在过去两次新星爆发中看到的那样。结合TNR发生时间的临近,基于前两颗新星($2026 \pm$ 3)之间80年的间隔,目前的吸积高状态增加了未来几年TNR发生在T CrB的可能性。

英文摘要:

Estimates of the accretion rate in symbiotic recurrent novae (RNe) often fall short of theoretical expectations by orders of magnitude. This apparent discrepancy can be resolved if the accumulation of mass by the white dwarf (WD) is highly sporadic, and most observations are performed during low states. Here we use a reanalysis of archival data from the Digital Access to a Sky Century @Harvard (DASCH) survey to argue that the most recent nova eruption in symbiotic RN T CrB, in 1946, occurred during -- and was therefore triggered by -- a transient accretion high state. Based on similarities in the optical light curve around 1946 and the time of the prior eruption, in 1866, we suggest that the WD in T CrB accumulates most of the fuel needed to ignite the thermonuclear runaways (TNRs) during accretion high states. A natural origin for such states is dwarf-nova like accretion-disk instabilities, which are expected in the presumably large disks in symbiotic binaries. The timing of the TNRs in symbiotic RNe could thus be set by the stability properties of their accretion disks. T CrB is in the midst of an accretion high state like the ones we posit led to the past two nova eruptions. Combined with the approach of the time at which a TNR would be expected based on the 80-year interval between the prior two novae ($2026 \pm$3), the current accretion high state increases the likelihood of a TNR occurring in T CrB in the next few years.

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