Claudia Conrad (AIP)

Open Cluster Groups and Complexes
When Mar 10, 2015 from 02:00 PM to 03:00 PM
  • Special Seminar
  • Colloquium
Where SH, Lecture hall
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It is generally agreed upon that stars typically form in open clusters and stellar associations, but little is known about structures in the Galactic open cluster population. Do open clusters and stellar associations form isolated or do they prefer to form in groups? Answering this question would provide new insight into star and cluster formation, as well as to the structure and evolution of our Milky Way. In the past decade the studies of open clusters groupings were either based solely on spatial criteria or also included tangential velocities for the identification of structures. Our approach was that genuine open cluster grouping would occupy a well defined area in the sky and show similar velocity vectors. Thus, it was only reasonable to use 6D phase-space information for the identification of open cluster groupings. We explored the Catalogue of Open Cluster Data (COCD) and could determine 6D phase-space information for 432 out of the 650 listed open clusters and compact associations. The group identification was performed using an adapted version of the Friends-of-Friends algorithm with linking lengths of 100 pc and 10-20 km/s. For the verification of the identified structures we applied Monte-Carlo simulations with randomised samples. The majority of the found gropings were pairs, accompanied by a few groups and one larger complex. The Monte-Carlo simulations revealed that the larger groups and the complex are most likely genuine, whereas the pairs are more likely to be by chance alignments. A closer look at the characteristics of the detected open cluster groupings suggested that they are likely to originate from a common molecular cloud.