High angular resolution observations of binary protostars [Elektronische Ressource] / presented by Xuepeng Chen


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Dissertationsubmitted to theCombined Faculties for the Natural Sciences and forMathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural Sciencespresented byXuepeng Chenborn in Guangde, ChinathOral examination: February 07 , 2008High angular resolution observationsof binary protostarsVersion 2.22007 August 27Online Publication VersionReferees: Prof. Dr. Thomas HenningProf. Dr. Ralf KlessenvAbstract: In this thesis I present a systematic effort to reveal the physical processesthat lead to the formation of binary stars. We have observed, at high angular resolution,thirteen isolated low-mass protostellar cores, using the Owens Valley Radio Observatorymillimeter array, the Australia Telescope Compact Array, and the IRAM Plateau de Bure+Interferometer array. Theobservations were mainly carried out in the N H (1–0) line and at23mmdustcontinuum. TheresultswerecomplementedbyinfrareddatafromtheSpitzer SpaceTelescope and the ESO Very Large Telescope. We find that binarity/multiplicity is frequentin the protostellar phase, though it is too early to derive a separation distribution. Thecircumstellar mass ratio distribution of binary protostars appears to be flat like that of moreevolved long-period main-sequence binary stars, and more than 75% of protobinary systemshave circumstellar mass ratios below 0.5.



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Published 01 January 2008
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