论文标题
棕色矮人的供体和光学上的薄积光盘，具有复杂的溪流冲击区域的候选者BW Sculptoris
A brown dwarf donor and an optically thin accretion disc with a complex stream impact region in the period-bouncer candidate BW Sculptoris
论文作者
论文摘要
我们介绍了WZ SGE型矮人Nova Nova BW SCL的多上观光镜和光度观测，这是一个时期的候选者。我们从供体恒星中检测到了多个辐照诱导的发射线，从而使径向速度变化以高精度测量。同样，使用吸收线MGII 4481和CAII K起源于吸收白矮人（WD）的光球，我们测量了WD及其重力红移的径向速度半增长速度。我们发现WD的质量为0.85 $ \ pm $ 0.04 m $ _ \ odot $，而供体是一个低质量对象，质量为0.051 $ \ pm $ 0.006 m $ _ \ odot $，远低于氢气燃料限制。使用NIR数据，我们对捐赠者的有效温度为$ \ Lessim $ 1600 K，对应于T光谱类型的棕色矮人。 BW SCL中的光学上的积分光盘具有非常低的光度$ \ Lessim $ 4 $ \ times 10^{30} $ erg s $^{ - 1} $，对应于非常低的质量增载率$ \ lyssim $ 7 $ $ 7 $ \ times 10^{ - 13} $ m $ $ _ $ _ $ _ \ odot $ $ $ $ $光盘的外部具有低密度，使流流向内盘区域。热点的最亮部分位于圆盘的圆形半径附近。热点是光学厚的，具有复杂的细长结构。根据测量的系统参数，我们讨论了系统的进化状态。
We present an analysis of multi-epoch spectroscopic and photometric observations of the WZ Sge-type dwarf nova BW Scl, a period-bouncer candidate. We detected multiple irradiation-induced emission lines from the donor star allowing the radial velocity variations to be measured with high accuracy. Also, using the absorption lines Mgii 4481 and Caii K originated in the photosphere of the accreting white dwarf (WD), we measured the radial velocity semi-amplitude of the WD and its gravitational redshift. We find that the WD has a mass of 0.85$\pm$0.04 M$_\odot$, while the donor is a low-mass object with a mass of 0.051$\pm$0.006 M$_\odot$, well below the hydrogen-burning limit. Using NIR data, we put an upper limit on the effective temperature of the donor to be $\lesssim$1600 K, corresponding to a brown dwarf of T spectral type. The optically thin accretion disc in BW Scl has a very low luminosity $\lesssim$4 $\times 10^{30}$ erg s$^{-1}$ which corresponds to a very low mass accretion rate of $\lesssim$7 $\times 10^{-13}$ M$_\odot$ year$^{-1}$. The outer parts of the disc have a low density allowing the stream to flow down to the inner disc regions. The brightest part of the hotspot is located close to the circularization radius of the disc. The hotspot is optically thick and has a complex, elongated structure. Based on the measured system parameters, we discuss the evolutionary status of the system.
