Institute of Astronomy

Efficient Formation of Exotic Binaries from Hierarchical Triples and Wide Binaries in the Field

SpeakerTalk DateTalk Series
Erez Michaely25 July 2016Binary Stars Talks

Abstract

Collisional dynamics in dense stellar cluster catalyse and enhance the formation of compact binaries and collisional products in these environments. Production of similar objects in the field is thought to explained by stellar evolution. Here we show that collisional dynamics in the field can play a major rule in producing exotic binaries when mediated by very wide binaries \left(>10^{3}au\right). In particular hierarchical triple and wide binaries in the field undergo multiple stellar encounters during the lifetime of the system. These encounters change the orbital elements of the wide (outer) binary. If the binary becomes sufficiently eccentric during the process its components strongly interact lead to tidal captures, collisions or mergers. In triple systems changes in the orbital properties of the outer binary may lead the system into a Kozai (secular) evolution. In this case the secular evolution can serve as an efficient mediator for the close collisional interaction in the inner binary. We find the production rate for X-ray binaries gravitational waves sources and merger products in the field can be dominated by these. 

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