首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Statistical models for HIPPARCOS binaries
Authors:Söderhjelm  S
Institution:(1) Lund Observatory, Box 43, 5-22100, Lund, Sweden
Abstract:A statistical model for the binaries in the solar neighbourhood is constructed, using schematic but plausible distribution functions for the semi-major axes, the mass-ratios, and the eccentricities. The model is lsquocalibratedrsquo to give correct numbers of observed visual binaries and is then used to study the (closer) binaries of relevance for the HIPPARCOS mission. One main purpose is to estimate the influence of astrometric binaries observed by their photocentres. It is found that some 500 such systems (out of the 100000 stars observed by HIPPARCOS) should show a detectably curved motion, while more than ten times more show an orbital proper motion bias greater than the HIPPARCOS accuracy 0Prime.002 yr–1. Also, a non-negligible fraction (1%) of all stars will be binaries with periods close to 1 year causing problems for the parallax determination. The main contribution to these figures is from faint Main-Sequence stars. The period-distribution for the lsquoresolvedrsquo HIPPARCOS binaries is also obtained, and for many of them the periods are fairly short (<100 yr). Such data as these are to be used as guidelines in the construction of reduction software for the HIPPARCOS observations.Communication presented at the International Conference on lsquoAstrometric Binariesrsquo, held on 13–15 June, 1984, at the Remeis-Sternwarte Bamberg, Germany, to commemorate the 200th anniversary of the birth of Friedrich Wilhelm Bessel (1784–1846).
Keywords:
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号