疑似吸积风前极型星II的圆偏振测量
Circular polarimetry of suspect wind-accreting pre-polars II
浏览论文内容
中文总结 AI 辅助
本研究通过偏振测量分析9个候选天体，确认4个为磁性白矮星系统，发现2个吸积风前极型星候选体，还明确了1个类新星激变变星及其他系统的部分性质，为研究白矮星磁场起源与双星演化提供了关键观测依据。
中文摘要 AI 辅助
白矮星磁场的起源是一个悬而未决的问题，且这类磁场在交互双星的演化中发挥着至关重要的作用。本研究针对所谓的前极型星（或称低吸积率极型星，LARPs，即磁性激变变星，其中质量损失的次星未充满洛希瓣，但系统通过恒星风发生吸积）中的白矮星磁场展开研究，这类系统对理解密近双星的磁制动和角动量演化具有关键意义。研究人员旨在从9个候选系统样本中识别出一组吸积风前极型星，同时尝试测量白矮星磁场并研究与吸积风前极型星相关的吸积几何。研究人员获取了目标天体的光学圆成像偏振测量和圆光谱偏振测量数据，用于模拟回旋辐射并估算白矮星的磁场强度。结果显示，在9个候选系统中，至少有4个可确认白矮星的磁性本质；其中1个系统ZTF J1737+4013似乎是食极型星，ZTF J2220+0721和ZTF J2353+4153是吸积风前极型星（或LARPs）的有力候选，第4个系统ZTF J0056+4926呈现出与前极型星特征不符的强可变Hα发射，不过该发射可能与供星的强活动有关，主导了光学光谱；另有1个系统ZTF J0504+2145可能是类新星激变变星，其余系统的确切性质仍不明确。
英文摘要
The origin of white dwarf magnetic fields is an open question. Furthermore, such fields play a vital role in the evolution of interacting binary stars. Here we present a study of white dwarf fields in so called pre-polars (or low accretion rate polars, LARPs , i.e. magnetic cataclysmic variables, where the mass losing secondary star is not in Roche lobe contact, but the systems experience accretion via stellar wind. Such systems play a crucial role in understanding the magnetic braking and the angular momentum evolution of close binaries. We aim to identify a set of wind-accreting pre-polars amongst our sample of nine candidate systems. We also attempt to measure the white dwarf magnetic fields and study the accretion geometry associated with wind-accreting pre-polars. We have obtained optical circular imaging photopolarimetry and circular spectropolarimetry of the targets. These are used to model the cyclotron emission and to estimate the white dwarf magnetic field strengths. We find that at least in four out of our nine candidate systems, we can confirm the magnetic nature of the white dwarf. Out of these, One system, ZTF J1737+4013, appears to be an eclipsing polar. Furthermore, ZTF J2220+0721 and ZTF J2353+4153 appear to be very strong candidates for wind-accreting pre-polars (or LARPs), with the fourth, ZTF J0056+4926, showing strong variable $H_α$ emission, atypical of pre-polars. However, the emission could be related to the strong activity of the donor star, dominating the optical spectrum. One system, ZTF J0504+2145, is likely a novalike CV. The exact nature of the other systems remains unclear.
