论文标题
被忽视的X射线发现了Polars：II：奇特的黯然失色的二进制
Neglected X-ray discovered polars: II: The peculiar eclipsing binary HY Eridani
论文作者
论文摘要
我们报告了Ecrelips的极性Hy ERI（RX J0501-0359）的X射线观测，以及其光度，分光光度计和光谱光学光学变化，在30年内收集了30年。轨道周期为2.855 h，hy eri落在2-3 h周期间隙的上边缘附近。在2011年之后，该系统延长了延长的低状态，并继续以低水平的水平吸收。我们提出了准确的无别名长期轨道象征，并报告了从2011年到2018年间隔10毫秒的高度重大变化。我们获得了高质量的日食光谱，该频谱以DM5-6 DWARF为DM5-6 DWARF，距离为DM5-6 DWAR，距离为$ d = 1050 = 1050 f = 1050 \ pm 110 $ pp。基于相位分辨的回旋子和Zeeman光谱法，我们将Hy Eri中的白矮人（WD）识别为一个两极增生器，几乎相反的增生点为28和30 mg。低态光谱的Zeeman分析揭示了一个复杂的磁场结构，我们通过多极模型拟合。我们从次级恒星的辐射面上检测到狭窄的发射线，其中毫克I $λ5170$，径向速度振幅为$ k_2'= 139 \ pm 10 $ km/s（90％的信心）跟踪次级比狭窄的H $α$线更可靠地跟踪次级。基于WD角半径的组合动力学分析和光谱测量，我们获得了$ M_1 = 0.42 \ pm 0.05 $ $ $ M_ \ odot $（90％置信误差）的主要质量（90％的置信误差），并将其确定为可能是WD或Hebrid Heco WD。次级是$ M_2 = 0.24 \ pm 0.04 $ $ $ m_ \ odot $的主要序列星，似乎略有膨胀。 Hy Eri的距离很大，缺乏相似的系统表明，低质量初级的极性杆子密度非常低。根据当前的理论，这些系统被诱发的逃亡传否破坏，这表明Hy Eri可能注定要破坏。
We report on the X-ray observations of the eclipsing polar HY Eri (RX J0501-0359), along with its photometric, spectrophotometric, and spectropolarimetric optical variations, collected over 30 years. With an orbital period of 2.855 h, HY Eri falls near the upper edge of the 2-3 h period gap. After 2011, the system went into a prolonged low state, continuing to accrete at a low level. We present an accurate alias-free long-term orbital ephemeris and report a highly significant period change by 10 ms that took place over the time interval from 2011 to 2018. We acquired a high-quality eclipse spectrum that shows the secondary star as a dM5-6 dwarf at a distance $d = 1050 \pm 110$ pc. Based on phase-resolved cyclotron and Zeeman spectroscopy, we identify the white dwarf (WD) in HY Eri as a two-pole accretor with nearly opposite accretion spots of 28 and 30 MG. The Zeeman analysis of the low state spectrum reveals a complex magnetic field structure, which we fit by a multipole model. We detected narrow emission lines from the irradiated face of the secondary star, of which Mg I $λ5170$ with a radial velocity amplitude of $K_2' = 139 \pm 10$ km/s (90% confidence) tracks the secondary more reliably than the narrow H$α$ line. Based on the combined dynamical analysis and spectroscopic measurement of the angular radius of the WD, we obtain a primary mass of $M_1 = 0.42 \pm 0.05$ $M_\odot$ (90% confidence errors), identifying it as a probable He WD or hybrid HeCO WD. The secondary is a main sequence star of $M_2 = 0.24 \pm 0.04$ $M_\odot$ that seems to be slightly inflated. The large distance of HY Eri and the lack of similar systems suggest a very low space density of polars with low-mass primary. According to current theory, these systems are destroyed by induced runaway mass transfer, suggesting that HY Eri may be doomed to destruction.
