University of Hertfordshire

From the same journal

From the same journal

Disentangling the spatial substructure of Cygnus OB2 from Gaia DR2

Research output: Contribution to journalArticle

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    Accepted author manuscript, 797 KB, PDF document

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  • S. R. Berlanas
  • N. Wright
  • A. Herrero
  • J. E. Drew
  • D. J. Lennon
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Original languageEnglish
Number of pages5
Pages (from-to)1838–1842
JournalMonthly Notices of the Royal Astronomical Society
Journal publication date1 Apr 2019
Volume484
Issue2
Early online date16 Jan 2019
DOIs
Publication statusPublished - 1 Apr 2019

Abstract

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.

Notes

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

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