This work was presented in the IAU symposium 307 entitled New Windows on Massive Stars which happened in Geneva, Switzerland, from 22 to 27 of June 2014.

The format of the presentation was poster.

Authors Bragança, G.; Lanz, T.; Daflon, S.; Cunha, K.; Garmany, C. D.; Glaspey, J. W.; Borges Fernandes, M.; Oey, M. S.; Bensby, T.

Abstract:

Abundance gradients are observed in other galaxies, with their metallicities decreasing outwards from the galactic centers. The abundance slopes for different elements may vary depending on the galactic morphology. In our Galaxy, the radial abundance gradients remain somewhat uncertain on the outer parts of the Galactic disk, due to the small number of studied stars located beyond the Perseus Arm. The aim of this study is to provide a large abundance database of distant stars in order to better constrain the Galactic gradient in the Outer Disk. We have obtained high-resolution, echelle spectra for a sample of 137 OB stars located towards the Galactic anti-center using the 6.5m Magellan Clay telescope + MIKE spectrograph. A subsample of 50 single stars presenting sharp absorption lines has been selected to carry out the abundance analysis. Stellar parameters, Silicon and Oxygen abundances are derived consistently based on non-LTE synthesis of hydrogen, helium, Silicon and Oxygen lines, requiring ionization balance of SiII/III/IV and O I/II/III. In this work, we present preliminary abundance results of our analysis.

You can download the poster here.

Please, cite this work as

Bragança, Gustavo; Lanz, T.; Daflon, S.; Cunha, K.; Garmany, C. D.; Glaspey, J. W.; Borges Fernandes, M.; Oey, M. S.; Bensby, T. (2014): A Spectroscopic Study of OB Stars Located on the Outer Galactic Disk. figshare. http://dx.doi.org/10.6084/m9.figshare.1050565

Acknowledgements: We acknowledge financial support of National Science Foundation, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior and the International Astronomomic Union. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France and of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration, 2013).