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Title: A near-infrared photometric study of Rho Ophiunchus, Cygnus OB7, and five galactic plane molecular clouds
Author: Mitchison, S. M.
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2012
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In this study, two nearby, low-mass star-forming regions (Ll688 in Rho Ophiuchus and L1003 in Cygnus OB7) were compared with a relatively unbiased sample of Galactic Plane molecular clouds < 2 kpc from the Sun. The study was motivated by a relative lack of unbiased surveys of this kind; most regions are surveyed following the discovery of significant formation. The photometric data here was obtained from the Wide Field Camera of the United Kingdom Infrared Telescope. Candid.te populations of young stellar objects were identified using near-infrared colour-colour diagrams and analysed systematically in order to compare their properties. The results were then compared with L1688 and L1003. The clustering properties in L1688 were analysed with respect to projected. millimetre core positions and a trend was found where clustering decreased with evolutionary stage. 81% of Class I sources coincided with cores whereas this was the case for only 50% of transition objects. Clustering analyses were conducted for the other cloud populations and found to be comparable to one another ~ possessing large mean nearest neighbour separations consistent with being relatively distributed associations. The cloud masses and mass distributions were analysed using extinction maps. The Galactic Plane candidate populations were found to be in the intermediate-mass range. These clouds and their populations displayed. considerable differences to the more active L1688, while being comparable to L1003, with relatively low star formation rates/area and efficiencies averaging 0.4 M0 Myr-l pc-2 and 0.6% respectively. The average star formation rate was similar to that predicted by the Kennicutt formula based. on cloud mass surface density alone. Star formation rate was found to be independent of total cloud mass; however, there was a linear correlation when the mass above a threshold density was considered, consistent with the yield of stars in a cloud depending simply on its dense gas mass.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available