An Interferometric and Spectroscopic Analysis of the Multiple Star System HD 193322

Abstract

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 that we use to determine its orbital motion around a close companion Ab2 ($P=312$ d) and around a distant third star Aa ($P=35$ y).We have also obtained long baseline interferometry of the target in the $K^{\prime }$-band with the CHARA Array that 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 $23M_{\odot }$, respectively, and their spectral line broadening indicates that they represent extremes of fast and slow projected rotational velocity, respectively.

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Cited by in corpus (10)

• The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
• The MiMeS survey of magnetism in massive stars: Magnetic analysis of the O-type stars
• Separated Fringe Packet Observations with the CHARA Array II: $\omega$ Andromeda, HD 178911, and ξ Cephei
• The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor
• MONOS: Multiplicity Of Northern O-type Spectroscopic systems. I. Project description and spectral classifications and visual multiplicity of previously known objects
• The Villafranca catalog of Galactic OB groups: I. Systems with O2-O3.5 stars
• X-ray irradiation of the winds in binaries with massive components
• Gaia DR2 distances to Collinder 419 and NGC 2264 and new astrometric orbits for HD 193 322 Aa,Ab and 15 Mon Aa,Ab
• A Coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, delta Orionis Aa: III. Analysis of Optical Photometric MOST and Spectroscopic (Ground Based) Variations
• Multiplicity of northern bright O-type stars with optical long baseline interferometry