EPoS Contribution
EPoS Contribution
Dense Core Mass Segregation in Orion A and B

Helen Kirk
NRC-Herzberg, Victoria, CA
Observations of stellar clusters show evidence for mass segregation, even in very young systems, but the debate is not yet settled as to whether this segregation is truly primordial. We shed new light on this question by examining mass segregation at an earlier phase, in dense cores. We analyze clusters of dense cores in the Orion A and B molecular clouds, including a large massive star-forming cluster around the Integral Shaped Filament, as well as numerous smaller low-mass star-forming groups. Using observations from the JCMT Gould Belt Survey and two independent analysis methods, we find that most of the dense core clusters appear to be mass segregated. This suggests that stellar clusters may have some degree of primordial mass segregation imprinted on them from the the dense core formation stage.
Caption: The tendency for a central location of the most massive core in each dense core cluster. The horizontal axis shows the ratio of the separation of the most massive dense core from the cluster centre ("offset") to the median offset of all cluster members. Randomly located most massive dense cores would tend to be equally distributed above and below an offset ratio of 1. Dense core clusters in Orion B are shown in green, while those in Orion A are shown in blue. The red asterisks show a similar analysis on young stellar clusters by Kirk & Myers 2011.
J. Lane, UVic, CA
the JCMT GBS team
Suggested Session: Cluster Formation