论文标题
ELM调查南。 I.有效寻找极低的质量白矮人
The ELM Survey South. I. An Effective Search for Extremely Low Mass White Dwarfs
论文作者
论文摘要
我们开始寻找极低的质量（$ m \ leq03m _ {\ odot} $，榆树）白色矮人（WDS），基于VST Atlas和Skymapper Surveys的光度法。我们使用类似的颜色选择方法与超速恒星调查。 Gaia Data Release 2可用后，我们切换到了Astrestric选择。我们使用先前已知的ELM白色矮人样本来证明这些对象在视差和幅度中占据了独特的参数空间。我们使用SOAR 410万望远镜测试基于GAIA的选择，并识别超过二十多个低质量的白色矮人，其中包括6个新的榆树白矮人二进制二进制室，其周期短至2小时。基于Gaia的选择的效率更高，使我们能够将ELM调查足迹扩展到南部的天空。我们确认我们的一名候选人J0500 $ - $ 0930，将成为最亮（$ g = 12.6 $ mag），最接近的（$ d = 72 $ pc）ELM WHITE DWARF二进制二进制目前已知。值得注意的是，该系统的过渡系外行星调查卫星（TESS）全画幅成像数据显示，在该系统的轨道时期（$ p = 9.5 $ h），低级（$ <0.1 $％），但可能从相关的光束效果上差异。另一个系统上的苔丝数据J0642 $ - $ 5605，揭示了由于潮汐变形ELM WD而导致的椭圆形变化。这些证明了苔丝全帧图像的力量，证实了相对明亮的紧凑型物体二进制的轨道时期。
We begin the search for extremely-low mass ($M\leq0.3M_{\odot}$, ELM) white dwarfs (WDs) in the southern sky based on photometry from the VST ATLAS and SkyMapper surveys. We use a similar color-selection method as the Hypervelocity star survey. We switched to an astrometric selection once Gaia Data Release 2 became available. We use the previously known sample of ELM white dwarfs to demonstrate that these objects occupy a unique parameter space in parallax and magnitude. We use the SOAR 4.1m telescope to test the Gaia-based selection, and identify more than two dozen low-mass white dwarfs, including 6 new ELM white dwarf binaries with periods as short as 2 h. The better efficiency of the Gaia-based selection enables us to extend the ELM Survey footprint to the southern sky. We confirm one of our candidates, J0500$-$0930, to become the brightest ($G=12.6$ mag) and closest ($d=72$ pc) ELM white dwarf binary currently known. Remarkably, the Transiting Exoplanet Survey Satellite (TESS) full-frame imaging data on this system reveals low-level ($<0.1$%) but significant variability at the orbital period of this system ($P=9.5$ h), likely from the relativistic beaming effect. TESS data on another system, J0642$-$5605, reveals ellipsoidal variations due to a tidally distorted ELM WD. These demonstrate the power of TESS full-frame images in confirming the orbital periods of relatively bright compact object binaries.
