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Post Info TOPIC: Cygnus OB7
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RE: Cygnus OB7
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Title: Near-IR Field Variable Stars in Cygnus OB7
Authors: Scott J. Wolk, Thomas S. Rice, Colin A. Aspin

We present a subset of the results of a three season, 124 night, near-infrared monitoring campaign of the dark clouds Lynds 1003 and Lynds 1004 in the Cygnus OB7 star forming region. In this paper, we focus on the field star population. Using three seasons of UKIRT J, H and K band observations spanning 1.5 years, we obtained high-quality photometry on 9,200 stars down to J=17 mag, with photometric uncertainty better than 0.04 mag. After excluding known disk bearing stars we identify 149 variables - 1.6% of the sample. Of these, about 60 are strictly periodic, with periods predominantly < 2 days. We conclude this group is dominated by eclipsing binaries. A few stars have long period signals of between 20 and 60 days. About 25 stars have weak modulated signals, but it was not clear if these were periodic. Some of the stars in this group may be diskless young stellar objects with relatively large variability due to cool star spots. The remaining ~60 stars showed variations which appear to be purely stochastic.

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Blobrana


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Posts: 131433
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Title: A Wide-Field Near-Ir H2 2.122m line survey of the Braid Nebula Star Formation Region in Cygnus OB7
Authors: T. Khanzadyan, C. J. Davis, C. Aspin, D. Froebrich, M. D. Smith, T. Yu. Magakian, T. Movsessian, G. H. Moriarty-Schieven, E. H. Nikogossian, T.-S. Pyo, T. L. Beck

Context. Outflows and jets are the first signposts of ongoing star formation processes in any molecular cloud, yet their study in optical bands provides limited results due to the large extinction present. Near-infrared unbiased wide-field observations in the H2 1-0 S(1) line at 2.122µm alleviates the problem, enabling us to detect more outflows and trace them closer to their driving sources.
Aims. As part of a large-scale multi-waveband study of ongoing star formation in the Braid Nebula Star Formation region, we focus on a one square degree region that includes Lynds Dark Nebula 1003 and 1004. Our goal is to find all of the near-infrared outflows, uncover their driving sources and estimate their evolutionary phase.
Methods. We use near-infrared wide-field observations obtained with WFCAM on UKIRT, in conjunction with previously-published optical and archival MM data, to search for outflows and identify their driving sources; we subsequently use colour-colour analysis to determine the evolutionary phase of each source.
Results. Within a one square degree field we have identified 37 complex MHOs, most of which are new. After combining our findings with other wide-field, multi-waveband observations of the same region we were able to discern 28 outflows and at least 18 protostars. Our analysis suggests that these protostars are younger and/or more energetic than those of the Taurus-Auriga region. The outflow data enable us to suggest connection between outflow ejection and repetitive FU Ori outburst events. We also find that star formation progresses from W to E across the investigated region.

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