2011/04/27 by Theo A. ten Brummelaar, David P. O'Brien, Brian D. Mason +18 · 16 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Interferometry #Orbit (dynamics) #Orbital motion #Proper motion #Star (game theory) #Stars #Stellar, planetary, and galactic studies #Visibility #astro-ph.SR
paper · pdf · doi:10.1088/0004-6256/142/1/21
published in The Astronomical Journal 142(1), 21 (Institute of Physics)
arxiv created 2011/04/27 · openalex publication_date 2011/06/09 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The star HD 193322 is a remarkable multiple system of massive stars that lies at the heart of the cluster Collinder 419. Here we report on new spectroscopic observations and radial velocities of the narrow-lined component Ab1 which we use to determine its orbital motion around a close companion Ab2 ( P = 312 days) and around a distant third star Aa ( P = 35 years). We have also obtained long baseline interferometry of the target in the K ' band with the CHARA Array which we use in two ways. First, we combine published speckle interferometric measurements with CHARA separated fringe packet measurements to improve the visual orbit for the wide Aa,Ab binary. Second, we use measurements of the fringe packet from Aa to calibrate the visibility of the fringes of the Ab1,Ab2 binary, and we analyze these fringe visibilities to determine the visual orbit of the close system. The two most massive stars, Aa and Ab1, have masses of approximately 21 and 23 M ☉ , respectively, and their spectral line broadening indicates that they represent extremes of fast and slow projected rotational velocity, respectively.