论文标题

击中新的低点:YY DRA的苔丝光曲线中独特的28小时堆积(do dra)

Hitting a New Low: The Unique 28 h Cessation of Accretion in the TESS Light Curve of YY Dra (DO Dra)

论文作者

Hill, Katherine L., Littlefield, Colin, Garnavich, Peter, Scaringi, Simone, Szkody, Paula, Mason, Paul A., Kennedy, Mark R., Shaw, Aarran W., Covington, Ava E.

论文摘要

我们介绍了中间极性YY DRACONIS(YY DRA,也称为DO DRA)的过渡系外行星测量卫星(TESS)光曲线。功率谱表明,尽管在大多数观察期间都有流馈积聚,但在2020年初,唯一的周期性信号是椭圆形变化,并且没有明显的闪烁。我们将这种低状态解释为完全停止积聚,这是一种在中间极性中仅观察到的现象。同时对这种淡淡状态的基于地面的观察结果表明,当积聚可以忽略不计时,yy dra淡入$ g = 17.37 \ pm0.12 $,我们推断出这是白矮人及其红色矮人伴侣的合并光电贡献的幅度。使用调查光度法,我们在2018 - 2019年确定了额外的低状态,在此期间,YY DRA反复淡入(但永远不会低于)此阈值。这意味着相对频繁的戒烟。可以使用Zeeman拆分的白矮人的田间强度来直接测量可忽略的增生发作期间的光谱观测。另外,我们搜索可变星星的新目录,以解决对该系统的适当标识符的长期争议。

We present the Transiting Exoplanet Surveying Satellite (TESS) light curve of the intermediate polar YY Draconis (YY Dra, also known as DO Dra). The power spectrum indicates that while there is stream-fed accretion for most of the observational period, there is a day-long, flat-bottomed low state at the beginning of 2020 during which the only periodic signal is ellipsoidal variation and there is no appreciable flickering. We interpret this low state to be a complete cessation of accretion, a phenomenon that has been observed only once before in an intermediate polar. Simultaneous ground-based observations of this faint state establish that when accretion is negligible, YY Dra fades to $g=17.37\pm0.12$, which we infer to be the magnitude of the combined photospheric contributions of the white dwarf and its red dwarf companion. Using survey photometry, we identify additional low states in 2018-2019 during which YY Dra repeatedly fades to -- but never below -- this threshold. This implies relatively frequent cessations in accretion. Spectroscopic observations during future episodes of negligible accretion can be used to directly measure the field strength of the white dwarf by Zeeman splitting. Separately, we search newly available catalogs of variable stars in an attempt to resolve the long-standing dispute over the proper identifier of this system.

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