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Title: A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors

Abstract

We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference ΔV < 4 down to separations as small as 0.''01. The sample includes 58 of the brighter members of Cyg OB2, one of the closest examples of an environment containing a large number of very young and massive stars. We resolved binary companions for 12 targets and confirmed the triple nature of one other target, and we offer evidence of marginally resolved companions for two additional stars. We confirm the binary nature of 11 of these systems from complementary adaptive optics imaging observations. The overall binary frequency in our study is 22% to 26% corresponding to orbital periods ranging from 20 to 20,000 yr. When combined with the known short-period spectroscopic binaries, the results support the hypothesis that the binary fraction among massive stars is >60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this verymore » luminous star.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
22340009
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 147; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GALAXIES; HYPOTHESIS; MASS; RADIO TELESCOPES; RESOLUTION; SENSORS; SPACE; STARS

Citation Formats

Caballero-Nieves, S. M., Gies, D. R., Jao, W.-C., E-mail: s.caballero@shef.ac.uk, E-mail: gies@chara.gsu.edu, E-mail: jao@chara.gsu.edu, and others, and. A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors. United States: N. p., 2014. Web. doi:10.1088/0004-6256/147/2/40.
Caballero-Nieves, S. M., Gies, D. R., Jao, W.-C., E-mail: s.caballero@shef.ac.uk, E-mail: gies@chara.gsu.edu, E-mail: jao@chara.gsu.edu, & others, and. A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors. United States. https://doi.org/10.1088/0004-6256/147/2/40
Caballero-Nieves, S. M., Gies, D. R., Jao, W.-C., E-mail: s.caballero@shef.ac.uk, E-mail: gies@chara.gsu.edu, E-mail: jao@chara.gsu.edu, and others, and. 2014. "A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors". United States. https://doi.org/10.1088/0004-6256/147/2/40.
@article{osti_22340009,
title = {A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors},
author = {Caballero-Nieves, S. M. and Gies, D. R. and Jao, W.-C., E-mail: s.caballero@shef.ac.uk, E-mail: gies@chara.gsu.edu, E-mail: jao@chara.gsu.edu and others, and},
abstractNote = {We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference ΔV < 4 down to separations as small as 0.''01. The sample includes 58 of the brighter members of Cyg OB2, one of the closest examples of an environment containing a large number of very young and massive stars. We resolved binary companions for 12 targets and confirmed the triple nature of one other target, and we offer evidence of marginally resolved companions for two additional stars. We confirm the binary nature of 11 of these systems from complementary adaptive optics imaging observations. The overall binary frequency in our study is 22% to 26% corresponding to orbital periods ranging from 20 to 20,000 yr. When combined with the known short-period spectroscopic binaries, the results support the hypothesis that the binary fraction among massive stars is >60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this very luminous star.},
doi = {10.1088/0004-6256/147/2/40},
url = {https://www.osti.gov/biblio/22340009}, journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 2,
volume = 147,
place = {United States},
year = {Sat Feb 01 00:00:00 EST 2014},
month = {Sat Feb 01 00:00:00 EST 2014}
}