Herrero, A, Berlanas, SR, Lennon, DJ, Wright, NJ and Drew, JE (2019) Disentangling the spatial substructure of Cygnus OB2 from Gaia DR2. Monthly Notices of the Royal Astronomical Society, 484 (2). 1838 -1842. ISSN 0035-8711

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For the first time, we have explored the spatial substructure of the Cygnus OB2 association using parallaxes from the recent second Gaia data release. We find significant line-of-sight substructure within the association, which we quantify using a parametrized model that reproduces the observed parallax distribution. This inference approach is necessary due to the non-linearity of the parallax distance transformation and the asymmetry of the resulting probability distribution. Using a Markov Chain Monte Carlo ensemble sampler and an unbinned maximum likelihood test, we identify two different stellar groups superposed on the association. We find the main Cygnus OB2 group at ∼1760 pc, further away than recent estimates have envisaged, and a foreground group at ∼1350 pc. We also calculate individual membership probabilities and identify outliers as possible non-members of the association.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2019 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astrometry, parallaxes, stars: distances, stars: early-type, stars: massive, open clusters and associations: individual: Cygnus OB2
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Q Science > QB Astronomy > QB799 Stars
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 11 Apr 2019 10:08
Last Modified: 11 Apr 2019 10:09
URI: https://eprints.keele.ac.uk/id/eprint/6181

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