标题： 解决异步极地1RXS J083842.1$-$282723的周期 显示英文标题

标题： Resolving the Periods of the Asynchronous Polar 1RXS J083842.1$-$282723

摘要： 1RXS J083842.1$-$282723 是一个几乎同步的磁性灾变变星，其 X 射线光变曲线简单。 虽然其轨道周期通过光学光谱学已较为明确地确定为$P_{\rm orb}=98.4$分钟，但对$P_{\rm spin}/P_{\rm orb}$的间接估计范围从 0.90 到 0.96，因为短 X 射线光变曲线无法将拍频周期确定到两倍因子。 我们分析了一次最近的 50 天 TESS 观测数据，以及持续 9 年的地基光学时间序列测光数据，这些数据共同测量了精确的拍频、轨道和自转周期，并使 X 射线和光学调制能够相位对齐。 尽管 X 射线光变曲线无法区分 16.11 或 32.22 小时的拍频周期，但所有光学证据都支持较长的值，每半拍频周期内发生完全的极区转换。 这将需要$P_{\rm spin}/P_{\rm orb}=0.952$。 长期的光学监测还显示吸积率下降，以及拍频折叠光变曲线的变化。 获得至少 32 小时时长的新 X 射线/光学观测将有助于检查吸积结构的任何相关变化，并确认自转和拍频周期。 显示英文摘要

摘要： 1RXS J083842.1$-$282723 is a nearly synchronous magnetic cataclysmic variable with a simple X-ray light curve. While its orbital period was fairly well established at $P_{\rm orb}=98.4$ minutes from optical spectroscopy, indirect estimates of $P_{\rm spin}/P_{\rm orb}$ ranged from 0.90 to 0.96 because the short X-ray light curves could not determine the beat period to a factor of 2. We analyze a recent 50 day TESS observation, and ground-based optical time-series photometry spanning 9 years, that together measure precise beat, orbit, and spin periods and enable the X-ray and optical modulations to be phase aligned. Although the X-ray light curves do not distinguish between a beat period of 16.11 or 32.22 hours, all of the optical evidence favors the longer value, with complete pole switching of accretion every half beat cycle. This would require $P_{\rm spin}/P_{\rm orb}=0.952$. Long-term optical monitoring also shows a decline in accretion rate, and a change in the beat-folded light curve. It would be useful to obtain a new X-ray/optical observation of at least 32 hours duration to examine any associated change in accretion structure, and confirm the spin and beat periods.