ORBITS, DISTANCE, AND STELLAR MASSES OF THE MASSIVE TRIPLE STAR σ ORIONIS

Journal Article · Thu Dec 01 00:00:00 EST 2016 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/0004-6256/152/6/213· OSTI ID:22862827

Schaefer, G. H.; Turner, N. H.; Brummelaar, T. ten; Farrington, C. D.; Sturmann, J.; Sturmann, L. ^[1]; Hummel, C. A. ^[2]; Gies, D. R.; Baron, F. ^[3]; Zavala, R. T. ^[4]; Monnier, J. D.; Che, X. ^[5]; Walter, F. M. ^[6]

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1. The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States)
2. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany)
3. Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States)
4. U.S. Naval Observatory, Flagstaff Station, 10391 W. Naval Observatory Road, Flagstaff, AZ 86001 (United States)
5. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)
6. Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

We present interferometric observations of the σ Orionis triple system using the CHARA Array, NPOI, and VLTI. Using these measurements, we spatially resolve the orbit of the close spectroscopic binary (Aa,Ab) for the first time and present a revised orbit for the wide pair (A,B). Combining the visual orbits with previously published radial velocity measurements and new radial velocities measured at CTIO, we derive dynamical masses for the three massive stars in the system of M{sub Aa} = 16.99 ± 0.20 M{sub ⊙}, M{sub Ab} = 12.81 ± 0.18 M{sub ⊙}, and M{sub B} = 11.5 ± 1.2 M{sub ⊙}. The inner and outer orbits in the triple are not coplanar, with a relative inclination of 120°–127°. The orbital parallax provides a precise distance of 387.5 ± 1.3 pc to the system. This is a significant improvement over previous estimates of the distance to the young σ Orionis cluster.

• OSTI ID: 22862827
• Journal Information: The Astronomical Journal (Online), Vol. 152, Issue 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION SPECTROSCOPY
BINARY STARS
DISTANCE
INCLINATION
MASS
ORBITS
RADIAL VELOCITY