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Galactic Center Youth: Orbits and Origins of the Young Stars in the Central Parsec

Lu, J. R. and Ghez, A. M. and Hornstein, S. D. and Morris, M. and Matthews, K. and Thompson, D. J. and Becklin, E. E. (2006) Galactic Center Youth: Orbits and Origins of the Young Stars in the Central Parsec. Journal of Physics: Conference Series, 54 . pp. 279-287. ISSN 1742-6596. http://resolver.caltech.edu/CaltechAUTHORS:LUJjpcs06

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Abstract

We present new proper motions for the massive, young stars at the Galactic Center, based on 10 years of diffraction limited data from the Keck telescopes. Our proper motion measurements now have uncertainties of only 1-2 km/s and allow us to explore the origin of the young stars that reside within the sphere of inflience of the supermassive black hole whose strong tidal forces make this region inhospitable for star formation. Their presence, however, may be explained either by in situ star formation in an accretion disk or as the remnants of a massive stellar cluster which spiraled in via dynamical friction. Earlier stellar velocity vectors were used to postulate that all the young stars resided in two counter-rotating stellar disks, which is consistent with both of the above formation scenarios. Our precise proper motions allow us, for the frst time, to determine the orbital parameters of each individual star and thereby to test the hypothesis that the massive stars reside in two stellar disks. Of the 26 young stars in this study that were previously proposed to lie on the inner, clockwise disk, we find that nearly all exhibit orbital constraints consistent with such a disk. On the other hand, of the 7 stars in this study previously proposed to lie in the outer, less well-defhed counter-clockwise disk, 6 exhibit inclinations that are inconsistent with such a disk, bringing into question the existence of the outer disk. Furthermore, for stars in the inner disk that have eccentricity constraints, we find several that have lower limits to the eccentricity of more than 0.4, implying highly eccentric orbits. This stands in contrast to simple accretion disk formation scenarios which typically predict predominantly circular orbits.


Item Type:Article
ORCID:
AuthorORCID
Lu, J. R.0000-0001-9611-0009
Additional Information:© Institute of Physics and IOP Publishing Limited 2006. Support for this work was provided by J.R.L.’s NSF Graduate Research Fellowship, NSF grant AST-0406816, and the NSF Science & Technology Center for AO, managed by UCSC (AST-9876783). The W.M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. Galactic Center Workshop 2006 — From the Center of the Milky Way to Nearby Low-Luminosity Galactic Nuclei, Bad Honnef, Germany, 18 to 22 April 2006. Journal of Physics: Conference Series, Volume 54, 2006.
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
NSFAST-0406816
NSFAST-9876783
W. M. Keck FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:LUJjpcs06
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:LUJjpcs06
Alternative URL:http://dx.doi.org/10.1088/1742-6596/54/1/044
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6907
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:02 Jan 2007
Last Modified:25 May 2017 19:18

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