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The massive star-forming region Cygnus OB2

Published online by Cambridge University Press:  18 January 2010

N. J. Wright  and
J. J. Drake
N. J. Wright
Affiliation:
Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
J. J. Drake
Affiliation:
Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
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Abstract

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We present results from a catalogue of 1696 X-ray point sources detected in the massive star-forming region Cygnus OB2, the majority of which have optical or near-infrared associations. We derive ages of 3.5 and 5.25 Myr for the stellar populations in our two fields, in agreement with recent studies that suggest that the central 1–3 Myr-old OB association is surrounded and contaminated by an older population with an age of 5–10 Myr. The fraction of sources with protoplanetary disks, as traced by K-band excesses, is unusually low. Although this has previously been interpreted as due to the influence of the large number of OB stars in Cyg OB2, contamination from an older population of stars in the region could also be responsible. An initial mass function is derived and found to have a slope of Γ = −1.27, in agreement with the canonical value. Finally, we introduce the recently approved Chandra Cygnus OB2 Legacy Survey that will image a 1 square degree area of the Cygnus OB2 association to a depth of 120~ks, likely detecting ~ 10 000 stellar X-ray sources.

Keywords

open clusters and associations: individual (Cygnus OB2)stars: pre–main-sequenceX-rays: stars
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S266: Star clusters: basic galactic building blocks throughout time and space , August 2009 , pp. 551 - 554
Copyright
Copyright © International Astronomical Union 2010

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