The Solar Neighborhood. XVI. Parallaxes from CTIOPI: Final Results from the 1.5 m Telescope Program
The Solar Neighborhood. XVI. Parallaxes from CTIOPI: Final Results from the 1.5 m Telescope Program
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太阳能社区。
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发表时间：
2006
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通讯作者：
P. Ianna
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作者：
E. Costa;R. Mendez;W. Jao;T. Henry;J. Subasavage;P. Ianna
三角视差，自行和VJ（RI）KC光度测定给出了25颗恒星（其中一个是零视差控制场）的目标的Cerro Tololo美洲天文台视差调查（CTIOPI），一个广泛的范围计划，旨在发现和表征附近的恒星。所提出的三角函数的视差和自行是最后用CTIO 1.5米望远镜获得的，该望远镜的目标是CTIOPI输入列表中较暗的子集。本文给出了22个系统的首次三角松弛，其中一个在10 pc以内（DENIS 0255-4700），另外10个在10 ~ 25 pc之间。距离为4.97 ± 0.10秒差距，光谱类型为L7.5 V，丹尼斯0255-4700是目前已知最接近的L矮星。此外，它的MV = 24.44，是绝对视星等测量中最暗的矮星。我们提出了五个额外的系统，值得跟进，和VRIJHKS测光和测光距离估计其中四个初步的三角函数。我们还提供了测光和距离估计21个其他有前途的目标在我们的输入列表中，确定的三角函数不可能; 13个可能比25 pc更接近。我们还提出了色幅和色色图，结合理论等时线从文献中，切向速度，MR和MJ，有助于确定我们的每个目标的一般性质。通过这种方式，我们发现了一个新的（光谱证实的）亚矮星和两个疑似极端的亚矮星，它们可能是这些物体中最极端的例子。我们还发现了几颗质量非常低的恒星，其中一些可能是褐矮星。这就结束了CTIOPI 1.5 m程序，从中我们得到了总共69个三角函数（55个最终的，6个初步的，和8个校准）。
Trigonometric parallaxes, proper motions and VJ(RI)KC photometry are given for 25 stars (of which one is a zero-parallax control field) targeted by the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI), a widely scoped program aimed at discovering and characterizing nearby stars. The trigonometric parallaxes and proper motions presented are the last that were obtained with the CTIO 1.5 m telescope, which targeted the fainter subset of the CTIOPI input list. First trigonometric parallaxes are given for 22 systems, of which one is within 10 pc (DENIS 0255-4700), and 10 of which are between 10 and 25 pc. At a distance of 4.97 ± 0.10 pc, and with a spectral type of L7.5 V, DENIS 0255-4700 is now the closest known L dwarf. In addition, with MV = 24.44, it is the faintest dwarf with a measured absolute visual magnitude. We present preliminary trigonometric parallaxes for five additional systems worthy of follow-up, and VRIJHKS photometry and photometric distance estimates for four of them. We also give photometry and distance estimates for 21 other promising targets in our input list for which definitive trigonometric parallaxes were not possible; 13 are likely to be closer than 25 pc. We also present color-magnitude and color-color diagrams, which, in combination with theoretical isochrones from the literature, tangential velocities, and MR and MJ, have aided to identify the general nature of each of our targets. We have in this way discovered one new (spectroscopically confirmed) subdwarf and two suspected extreme subdwarfs that could be among the most extreme cases of these objects. We have also identified several very low mass stars, a few of which could be brown dwarfs. This concludes the CTIOPI 1.5 m program, from which we have derived a total of 69 trigonometric parallaxes (55 definitive, 6 preliminary, and 8 calibration).