标题： 太阳邻域。 XXI。 CTIOPI 0.9米项目视差结果：25秒差距白矮星样本的20个新成员 显示英文标题

标题： The Solar Neighborhood. XXI. Parallax Results from the CTIOPI 0.9m Program: 20 New Members of the 25 Parsec White Dwarf Sample

摘要： 我们展示了25秒差距（pc）白矮星样本中的20个新成员的精确三角视差，这是DENSE项目（附近恒星遗迹的发现与评估，http://www.DenseProject.com）的一部分。此前，总共有112个白矮星系统通过三角视差被定位在25秒差距以内，其中99个的三角视差已知误差小于10%。因此，本工作中展示的20个新成员使准确位于25秒差距以内的白矮星数量增加了20%。此外，我们还更新了ASPENS计划（近距恒星周围行星的天文学搜索，监测附近南部红矮星和白矮星的天文学扰动）观测到的10秒差距以内7个已知白矮星的视差。包括一些白矮星伴星和超过25秒差距的白矮星，我们总共提供了33个三角视差。我们对白矮星进行大气建模以确定物理参数（即有效温度、log g、质量以及白矮星年龄）。最后，识别出一个新的ZZ Ceti脉动白矮星，并对两个显示近红外连续吸收的混合H/He大气冷却白矮星施加了修订后的限制条件。 显示英文摘要

摘要： We present accurate trigonometric parallaxes for 20 new members of the 25 pc white dwarf sample as part of the DENSE project (Discovery and Evalution of Nearby Stellar Embers, http://www.DenseProject.com). Previously, there were a total of 112 white dwarf systems with trigonometric parallaxes placing them within 25 pc and of these, 99 have trigonometric parallaxes known to better than 10%. Thus, the 20 new members presented in this work represent a 20% increase in the number of white dwarfs accurately known to be within 25 pc. In addition, we present updated parallaxes for seven known white dwarfs within 10 pc that have been observed as part of the ASPENS initiative (Astrometric Search for Planets Encircling Nearby Stars) to monitor nearby southern red and white dwarfs for astrometric perturbations from unseen companions. Including a few white dwarf companions and white dwarfs beyond 25 pc, we present a total of 33 trigonometric parallaxes. We perform atmospheric modeling for white dwarfs to determine physical parameters (i.e., effective temperature, log g, mass, and white dwarf age). Finally, a new ZZ Ceti pulsating white dwarf was identified and revised constraints are placed on two mixed H/He atmosphere cool white dwarfs that display continuum absorption in the near-infrared.