TY - JOUR
T1 - ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem
AU - Gardner, Tyler
AU - Monnier, John D.
AU - Fekel, Francis C.
AU - Schaefer, Gail
AU - Johnson, Keith J.C.
AU - Le Bouquin, Jean Baptiste
AU - Kraus, Stefan
AU - Anugu, Narsireddy
AU - Setterholm, Benjamin R.
AU - Labdon, Aaron
AU - Davies, Claire L.
AU - Lanthermann, Cyprien
AU - Ennis, Jacob
AU - Ireland, Michael
AU - Kratter, Kaitlin M.
AU - Ten Brummelaar, Theo
AU - Sturmann, Judit
AU - Sturmann, Laszlo
AU - Farrington, Chris
AU - Gies, Douglas R.
AU - Klement, Robert
AU - Adams, Fred C.
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
PY - 2021/1
Y1 - 2021/1
N2 - 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 <0.″2 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.
AB - 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 <0.″2 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.
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U2 - 10.3847/1538-3881/abcf4e
DO - 10.3847/1538-3881/abcf4e
M3 - Article
AN - SCOPUS:85098545973
SN - 0004-6256
VL - 161
JO - Astronomical Journal
JF - Astronomical Journal
IS - 1
M1 - 40
ER -