Elemental abundance measurements for lanthanum, europium, and iron are presented for 504 stars in the solar neighborhood. The bulk of the data are planet search spectra taken with HIRES on the Keck I telescope at R=50,000, but a subset of 45 kinematically selected stars were observed on the Harlan J. Smith Telescope at McDonald Observatory at R=60,000 and S/N=100 at the 3988 angstrom lanthanum line and S/N=250 around 5240 angstrom near the iron lines. Statistical analyses of stellar kinematics in the solar neighborhood reveal much kinematic substructure in the disk, though it is not readily apparent whether this substructure is extragalactic or dynamical in origin. Much of the substructure can be quickly identified as well known moving groups of stars such as the Hercules, Sirius, and Hyades stellar streams. Additionally, the subset of kinematically selected stars observed at McDonald Observatory are members of a stellar stream putatively identified by Amina Helmi as part of a merger remnant. Taking advantage of a large data set and a homogeneous spectral analysis, a Kolmogorov-Smirnov hypothesis test is applied to investigate the possibility that these kinematic structures are chemically distinct from the Galactic Disk. In all cases, the kinematic streams have chemistries roughly consistent with the Galactic disk trends, although the statistical analyses suggest some subtle variations. The accretion hypothesis is not completely ruled out for Helmi's stream, but the chemical variations are interpreted primarily in terms of dynamical effects.
|Advisor:||Carney, Bruce W.|
|Commitee:||Cecil, Gerald, Champagne, Arthur E., Heitsch, Fabian, Kannappan, Sheila|
|School:||The University of North Carolina at Chapel Hill|
|Department:||Physics & Astronomy|
|School Location:||United States -- North Carolina|
|Source:||DAI-B 73/06, Dissertation Abstracts International|
|Keywords:||Chemical tagging, Disk, Elemental abundance, Kinematic substructures, Solar neighborhood, Stellar kinematics|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be