%0 Generic %1 nagasawa2017chemical %A Nagasawa, D. Q. %A Marshall, J. L. %A Simon, J. D. %A Hansen, T. T. %A Li, T. S. %A Bernstein, R. A. %A Balbinot, E. %A Drlica-Wagner, A. %A Pace, A. B. %A Strigari, L. E. %A Pellegrino, C. M. %A DePoy, D. L. %A Suntzeff, N. B. %A Bechtol, K. %A Abbott, T. M. C. %A Abdalla, F. B. %A Allam, S. %A Annis, J. %A Benoit-Lévy, A. %A Bertin, E. %A Brooks, D. %A Rosell, A. Carnero %A Kind, M. Carrasco %A Carretero, J. %A Cunha, C. E. %A D'Andrea, C. B. %A da Costa, L. N. %A Davis, C. %A Desai, S. %A Doel, P. %A Eifler, T. F. %A Flaugher, B. %A Fosalba, P. %A Frieman, J. %A García-Bellido, J. %A Gaztanaga, E. %A Gerdes, D. W. %A Gruen, D. %A Gruendl, R. A. %A Gschwend, J. %A Gutierrez, G. %A Hartley, W. G. %A Honscheid, K. %A James, D. J. %A Jeltema, T. %A Krause, E. %A Kuehn, K. %A Kuhlmann, S. %A Kuropatkin, N. %A March, M. %A Miquel, R. %A Nord, B. %A Roodman, A. %A Sanchez, E. %A Santiago, B. %A Scarpine, V. %A Schindler, R. %A Schubnell, M. %A Sevilla-Noarbe, I. %A Smith, M. %A Smith, R. C. %A Soares-Santos, M. %A Sobreira, F. %A Suchyta, E. %A Tarle, G. %A Thomas, D. %A Tucker, D. L. %A Walker, A. R. %A Wechsler, R. H. %A Wolf, R. C. %A Yanny, B. %D 2017 %K alpha enhancement metal poor star %T Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I %U http://arxiv.org/abs/1708.02290 %X We present chemical abundance measurements of three stars in the ultra-faint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high resolution spectroscopic observations we measure the metallicity of the three stars as well as abundance ratios of several $\alpha$-elements, iron-peak elements, and neutron-capture elements. The abundance pattern is relatively consistent among all three stars, which have a low average metallicity of Fe/H $-2.6$ and are not $\alpha$-enhanced ($\alpha$/Fe $0.0$). This result is unexpected when compared to other low-metallicity stars in the Galactic halo and other ultra-faint dwarfs and hints at an entirely different mechanism for the enrichment of Hor I compared to other satellites. We discuss possible scenarios that could lead to this observed nucleosynthetic signature including extended star formation, a Population III supernova, and a possible association with the Large Magellanic Cloud.

@misc{nagasawa2017chemical, abstract = {We present chemical abundance measurements of three stars in the ultra-faint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high resolution spectroscopic observations we measure the metallicity of the three stars as well as abundance ratios of several $\alpha$-elements, iron-peak elements, and neutron-capture elements. The abundance pattern is relatively consistent among all three stars, which have a low average metallicity of [Fe/H] $\sim -2.6$ and are not $\alpha$-enhanced ([$\alpha$/Fe] $\sim 0.0$). This result is unexpected when compared to other low-metallicity stars in the Galactic halo and other ultra-faint dwarfs and hints at an entirely different mechanism for the enrichment of Hor I compared to other satellites. We discuss possible scenarios that could lead to this observed nucleosynthetic signature including extended star formation, a Population III supernova, and a possible association with the Large Magellanic Cloud.}, added-at = {2017-08-09T10:22:58.000+0200}, author = {Nagasawa, D. Q. and Marshall, J. L. and Simon, J. D. and Hansen, T. T. and Li, T. S. and Bernstein, R. A. and Balbinot, E. and Drlica-Wagner, A. and Pace, A. B. and Strigari, L. E. and Pellegrino, C. M. and DePoy, D. L. and Suntzeff, N. B. and Bechtol, K. and Abbott, T. M. C. and Abdalla, F. B. and Allam, S. and Annis, J. and Benoit-Lévy, A. and Bertin, E. and Brooks, D. and Rosell, A. Carnero and Kind, M. Carrasco and Carretero, J. and Cunha, C. E. and D'Andrea, C. B. and da Costa, L. N. and Davis, C. and Desai, S. and Doel, P. and Eifler, T. F. and Flaugher, B. and Fosalba, P. and Frieman, J. and García-Bellido, J. and Gaztanaga, E. and Gerdes, D. W. and Gruen, D. and Gruendl, R. A. and Gschwend, J. and Gutierrez, G. and Hartley, W. G. and Honscheid, K. and James, D. J. and Jeltema, T. and Krause, E. and Kuehn, K. and Kuhlmann, S. and Kuropatkin, N. and March, M. and Miquel, R. and Nord, B. and Roodman, A. and Sanchez, E. and Santiago, B. and Scarpine, V. and Schindler, R. and Schubnell, M. and Sevilla-Noarbe, I. and Smith, M. and Smith, R. C. and Soares-Santos, M. and Sobreira, F. and Suchyta, E. and Tarle, G. and Thomas, D. and Tucker, D. L. and Walker, A. R. and Wechsler, R. H. and Wolf, R. C. and Yanny, B.}, biburl = {https://www.bibsonomy.org/bibtex/24fa1c8e1a508437ee1c5b28d56b7fea2/miki}, description = {[1708.02290] Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I}, interhash = {4c708af3c54110cb50251558be5ce888}, intrahash = {4fa1c8e1a508437ee1c5b28d56b7fea2}, keywords = {alpha enhancement metal poor star}, note = {cite arxiv:1708.02290}, timestamp = {2017-08-09T10:22:58.000+0200}, title = {Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I}, url = {http://arxiv.org/abs/1708.02290}, year = 2017 }