The observed distribution of spectroscopic binaries from the Anglo-Australian planet search

Jenkins, J. S. and Diaz, M. and Jones, H. R. A. and Butler, R. P. and Tinney, C. G. and O'Toole, S. J. and Carter, B. D. and Wittenmyer, R. A. and Pinfield, D. J. (2015) The observed distribution of spectroscopic binaries from the Anglo-Australian planet search. Monthly Notices of the Royal Astronomical Society, 453 (2). pp. 1439-1457. ISSN 0035-8711

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We report the detection of sixteen binary systems from the Anglo-Australian Planet Search. Solutions to the radial velocity data indicate that the stars have companions orbiting with a wide range of masses, eccentricities and periods. Three of the systems potentially contain brown-dwarf companions while another two have eccentricities that place them in the extreme upper tail of the eccentricity distribution for binaries with periods less than 1000 d. For periods up to 12 years, the distribution of our stellar companion masses is fairly flat, mirroring that seen in other radial velocity surveys, and contrasts sharply with the current distribution of candidate planetary masses, which rises strongly below 10 MJ. When looking at a larger sample of binaries that have FGK star primaries as a function of the primary star metallicity, we find that the distribution maintains a binary fraction of ∼43 ± 4 per cent between −1.0 and +0.6 dex in metallicity. This is in stark contrast to the giant exoplanet distribution. This result is in good agreement with binary formation models that invoke fragmentation of a collapsing giant molecular cloud, suggesting that this is the dominant formation mechanism for close binaries and not fragmentation of the primary star's remnant protoplanetary disc.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Access to Published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 19 Apr 2016 23:50
Last Modified: 17 May 2017 02:42
Uncontrolled Keywords: catalogues binaries; spectroscopic brown dwarfs stars; fundamental parameters stars; solar-type
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1093/mnras/stv1596

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