分离白矮星-主序星双星系统中自引力透镜效应的有限透镜效应
Finite-Lens Effect on Self-Lensing in detached White Dwarfs-Main Sequence Binary Systems
AI总结：
本研究针对分离白矮星-主序星双星系统的有限透镜效应，结合数值与解析方法分析自透镜与掩食的竞争关系，明确不同轨道周期、白矮星质量下的主导效应及误差范围，揭示伴星尺寸对信号的双重影响。
摘要：
在包含一颗白矮星（WD）和一颗主序星的（WDMS）近共面、分离双星系统中，当源恒星从致密伴星后方经过时，其光线会发生偏折并被放大。同时，其像的部分区域会被白矮星的星盘遮挡。这两种效应同时发生，观测者接收到的恒星光因有限透镜尺寸而被放大且部分被遮挡。我们采用逆射线追踪（IRS，逆射线射击法）对不同WDMS双星系统中的这些效应进行数值研究，并采用贴近实际的近似关系进行解析研究。对于轨道周期≳300天、且白矮星质量M_WD≳0.2倍太阳质量（M_WD为白矮星质量）的WDMS系统，有限透镜效应导致的透镜效应强于掩食效应；而对于质量高于太阳质量的大质量白矮星，则不会发生掩食。在低质量白矮星（M_WD≲0.2倍太阳质量）、轨道周期T≲50天的近轨道系统中，掩食效应在自透镜信号中占主导。当白矮星半径等于√2倍爱因斯坦半径时，掩食与自透镜效应会相互抵消，且该结果与源星半径无关，这一规律给出了轨道周期与白矮星质量之间的递减关系。我们评估了使用已知解析关系计算自透镜/掩食归一化流量最大偏差时产生的误差，得出结论：当轨道周期T=30、100、300天时，这些误差分别可达0.002、0.08、0.03。WDMS系统中恒星伴星的尺寸具有双重作用：它会降低自透镜/掩食信号的深度，但会增大信号的宽度。
英文摘要：
In an edge-on and detached binary system, including a white dwarf (WD) and a main-sequence star (WDMS), when the source star is passing behind the compact companion its light is bent and magnified. Meanwhile, some part of its images' area is obscured by the WD's disk. These two effects occur simultaneously, and the observer receives the stellar light magnified and partially obscured due to the finite-lens size. We study these effects in different WDMS binary systems numerically using inverse-ray-shooting (IRS) and analytically using approximate relations close to reality. For WDMS systems with long orbital periods $\gtrsim 300$ days and $M_{\rm{WD}}\gtrsim 0.2 M_{\sun}$ ($M_{\rm{WD}}$ is the mass of WD), lensing effects dominate the occultations due to finite-lens effects, and for massive WDs with masses higher than solar mass no occultation happens. The occultations dominate self-lensing signals in systems with low-mass WDs($M_{\rm WD}\lesssim 0.2 M_{\sun}$) in close orbits with short orbital periods $T\lesssim 50$ days. The occultation and self-lensing cancel each other out when the WD's radius equals $\sqrt{2}$ times the Einstein radius, regardless of the source radius, which offers a decreasing relation between the orbital periods and WDs' mass. We evaluate the errors in maximum deviations in self-lensing/occultation normalized flux which are made by using its known analytical relation and conclude that these errors could be up to $0.002,~0.08,~0.03$ when the orbital period is $T=30,~100,~300$ days, respectively. The size of stellar companions in WDMSs has a twofold manner as it decreases the depth of self-lensing/occultation signals but enlarges their width.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
