文章基本信息

标题：An Updated 2017 Astrometric Solution for Betelgeuse
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作者：G. M. Harper ; A. Brown ; E. F. Guinan 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2017
卷号：154
期号：1
页码：1-9
DOI：10.3847/1538-3881/aa6ff9
语种：English
出版社：American Institute of Physics
摘要：We provide an update for the astrometric solution for the Type II supernova progenitor Betelgeuse using the revised Hipparcos Intermediate Astrometric Data (HIAD) of van Leeuwen, combined with existing VLA and new e-MERLIN and ALMA positions. The 2007 Hipparcos refined abscissa measurements required the addition of so-called Cosmic Noise of 2.4 mas to find an acceptable 5-parameter stochastic solution. We find that a measure of radio Cosmic Noise should also be included for the radio positions because surface inhomogeneities exist at a level significant enough to introduce additional intensity centroid uncertainty. Combining the 2007 HIAD with the proper motions based solely on the radio positions leads to a parallax of mas ( pc), smaller than the Hipparcos 2007 value of 6.56 ± 0.83 mas ( pc). Furthermore, combining the VLA and new e-MERLIN and ALMA radio positions with the 2007 HIAD, and including radio Cosmic Noise of 2.4 mas, leads to a nominal parallax solution of 4.51 ± 0.80 mas ( pc), which, while only different from the 2008 solution of Harper et al., is 2.6σ different from the solution of van Leeuwen. An accurate and precise parallax for Betelgeuse is always going to be difficult to obtain because it is small compared to the stellar angular diameter ( mas). We outline an observing strategy utilizing future mm and sub-mm high-spatial resolution interferometry that must be used if substantial improvements in the precision and accuracy of the parallax and distance are to be achieved.
关键词：astrometry ; stars: distances ; stars: fundamental parameters ; stars: individual (α Ori)