Chemical and kinematic properties of bright metal poor stars

In this work, I analyze the high-resolution spectra of 20 stars, chosen for their low metallicity [Fe/H] </~ -2.5 and proximity to the sun. Using these spectra I model the atmospheres of these stars by determing stellar parameters {Teff, log(g), [mu], [Fe/H]} and obtain also their chemical abundances for 17 elements including Fe, C, Sr, and Ba. Three of these stars are found to possess an overabundance of Carbon relative to Iron. Combining these chemical abundances with those from previously analyzed spectra from the same bright metal-poor star sample, I perform orbit determination and integration on a total of 59 metal-poor stars and extract their kinematic parameters. I also explore how these results depend on the assumed mass of the Milky Way. These chemical and kinematic results are then combined and compared with comparatively metal-rich (-2.5 </~ [Fe/H] </~ 0) samples; a conal distribution of velocity components with respect to metallicity is observed, as well as two distinct populations in eccentricity. The 59 bright metal-poor stars were identified as residing in the inner halo of the Milky Way.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2015

Author dc:creator

• Xu, Weishuang Linda

Advisor dc:contributor.advisor

• Anna Frebel.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/100325

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/100325