ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem
- Astronomy Department, University of Michigan, Ann Arbor, MI 48109 (United States)
- Center of Excellence in Information Systems, Tennessee State University, Nashville, TN 37209 (United States)
- The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91203 (United States)
- Institut de Planetologie et d’Astrophysique de Grenoble, Grenoble F-38058 (France)
- Astrophysics Group, Department of Physics & Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
- Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ, 85721 (United States)
- Institute of Astronomy, KU Leuven, Celestijnenlaan200D, B-3001, Leuven (Belgium)
- Research School of Astronomy & Astrophysics, Australian National University, Canberra ACT 2611 (Australia)
Ground-based optical long-baseline interferometry has the power to measure the orbits of close binary systems at ∼10 μas precision. This precision makes it possible to detect “wobbles” in the binary motion due to the gravitational pull from additional short-period companions. We started the ARrangement for Micro-Arcsecond Differential Astrometry (ARMADA) survey with the Michigan Infra-Red Combiner (MIRC)/MIRC-X instrument at the Center for High Angular Resoloution Astronomy (CHARA) array for the purpose of detecting giant planets and stellar companions orbiting individual stars in binary systems. We describe our observations for the survey, and introduce the wavelength calibration scheme that delivers precision at the tens of microarcseconds level for <02 binaries. We test our instrument performance on a known triple system, κ Peg, and show that our survey is delivering a factor of 10 better precision than previous similar surveys. We present astrometric detections of tertiary components to two B-type binaries: a 30 day companion to α Del, and a 50 day companion to ν Gem. We also collected radial velocity data for α Del with the Tennessee State University Automated Spectroscopic Telescope at Fairborn Observatory. We are able to measure the orbits and masses of all three components in these systems. We find that the previously published radial velocity orbit for the inner pair of ν Gem is not consistent with our visual orbit. The precision achieved for these orbits suggests that our ARMADA survey will be successful at discovering new compact triple systems to A/B-type binary systems, leading to better statistics of hierarchical system architectures and formation history.
- OSTI ID:
- 23159077
- Journal Information:
- The Astronomical Journal (Online), Vol. 161, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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