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S. M. Caballero-Nieves, D. R. Gies, L. C. Roberts & N. H. Turner

Cyg OB2 Unveiled: The Search for Astrometric Companions

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Open Access

Abstract

We present results from a high angular resolution survey of the most massive stars in the nearby Cygnus OB2 association. Using the NIRI instrument and ALTAIR AO system on Gemini North, we obtained J, H and K band observations of 75 O- and B-type association members to search for astrometric companions. This search is sensitive to companions in the separation range of 0.08 – 10″ with a magnitude difference less than 11 mag. The detected sample begins to fill in the period gap between astrometric and spectroscopic binaries. From photometric colors, we find that many of these companions appear to be very young, red stars. Using a statistical method to estimate field contamination, 42% of our targets have at least one highly probable companion.

To cite this article

S. M. Caballero-Nieves, D. R. Gies, L. C. Roberts & N. H. Turner, «Cyg OB2 Unveiled: The Search for Astrometric Companions», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 80 - Année 2011, 639 - 643 URL : https://popups.uliege.be/0037-9565/index.php?id=3097.

About: S. M. Caballero-Nieves

Georgia State University, Atlanta, GA, USA

About: D. R. Gies

Georgia State University, Atlanta, GA, USA

About: L. C. Roberts

JPL/California Institute of Technology, Pasadena, CA, USA

About: N. H. Turner

GSU CHARA Array, Mount Wilson, CA, USA