论文标题
突然变化的极低质量比接触二进制的第一个光度和轨道时期调查，TYC 4002-2628-1
The First Photometric and Orbital Period Investigation of an Extremely Low Mass Ratio Contact Binary with a Sudden Period Change, TYC 4002-2628-1
论文作者
论文摘要
在2020年11月至2021年11月之间，获得了完全黯然失色的二元系统TYC 4002-2628-1的光度观察。为了确定恒星大气参数，在中国国家天文观测值（NAOC）的2.16 m望远镜（NAOC）的2.16 m望远镜（NAOC）中拍摄了光谱图像。 TYC 4002-2628-1是一个低振幅（$ V $ band的0.15 mag），短期（0.3670495 d），与二进制的二进制次要二进制以二级日食。固有的光曲线变化和O'Connell效应的逆转在光曲线中检测到，这可能是由于斑点活性引起的。根据从多波段时间序列光曲线得出的光度法解决方案，TYC 4002-2628-1是极低的质量比触点二进制，质量比为$ q \ sim $ 0.0482，填充因子为$ f \ sim5 \％$。通过分析$ O-C $变化，我们发现当BJD <2458321时，其轨道时期保持不变。然后，轨道周期突然发生在BJD 2458743左右，$ dp/dt = 1.62 \ times {10^{ - 5}} day \ cdot yr^{ - 1} = 140 $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ cdot centry^{ - 1} $。 如果得到确认，TYC 4002-2628-1将是迄今为止轨道周期最高的接触二进制二进制二进制二进制。通过调查轨道角动量与旋转角动量的比率（$ j_ {orb} $/$ j_ {spin} $ $ <3 $），不稳定性比率（$ q_ {inst}/q = 1.84$）和不稳定性分离（$ a_ { 候选人。
Photometric observations for the totally eclipsing binary system TYC 4002-2628-1, were obtained between November 2020 and November 2021. To determine the stellar atmospheric parameters, a spectral image was taken with the 2.16 m telescope at National Astronomical Observatory of China (NAOC). TYC 4002-2628-1 is a low-amplitude (about 0.15 mag for $V$ band), short-period (0.3670495 d), contact eclipsing binary with a total secondary eclipse. Intrinsic light curve variations and the reversal of the O'Connell effect are detected in the light curves, which may be due to spot activity. Based on the photometric solutions derived from the multi-band time series light curves, TYC 4002-2628-1 is an extremely low mass ratio contact binary with a mass ratio of $q\sim$ 0.0482 and a fill-out factor of $f\sim5\%$. By analyzing the $O-C$ variations, we find that its orbital period remains unchanged when BJD < 2458321 . Then the orbital period changed suddenly around BJD 2458743 and has an increasing rate of $dP/dt=1.62\times{10^{-5}}day\cdot yr^{-1}=140$ $second\cdot century^{-1}$ . If confirmed, TYC 4002-2628-1 would be the contact binary with the highest orbital period increasing rate so far. By investigating the ratio of orbital angular momentum to the spin angular momentum ( $J_{orb}$/$J_{spin}$ $<3$) , the instability mass ratio ($q_{inst}/q=1.84$) and the instability separation ($A_{inst}/A=1.35$), TYC 4002-2628-1 can be regarded as a merger candidate.
