학술논문
Chemical Analysis of the Brightest Star of the Cetus II Ultra-Faint Dwarf Galaxy Candidate
Document Type
Working Paper
Author
Webber, K. B.; Hansen, T. T.; Marshall, J. L.; Simon, J. D.; Pace, A. B.; Mutlu-Pakdil, B.; Drlica-Wagner, A.; MartÍnez-VÁzquez, C. E.; Aguena, M.; Allam, S. S.; Alves, O.; Bertin, E.; Brooks, D.; Rosell, A. Carnero; Carretero, J.; Da Costa, L. N.; De Vicente, J.; Doel, P.; Ferrero, I.; Friedel, D.; Frieman, J.; GarcÍa-Bellido, J.; Giannini, G.; Gruen, D.; Gruendl, R. A.; Hinton, S. R.; Hollowood, D. L.; Honscheid, K.; Kuehn, K.; Mena-FernÁndez, J.; Menanteau, F.; Miquel, R.; Ogando, R. L. C.; Pereira, M. E. S.; Pieres, A.; MalagÓn, A. A. Plazas; Sanchez, E.; Santiago, B.; Smith, J. Allyn; Smith, M.; Suchyta, E.; Tarle, G.; To, C.; Weaverdyck, N.; Yanny, B.
Source
Subject
Language
Abstract
We present a detailed chemical abundance analysis of the brightest star in the ultra-faint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra. For this star, DES J011740.53-173053, abundances or upper limits of 18 elements from Carbon to Europium are derived. Its chemical abundances generally follow those of other UFD galaxy stars, with a slight enhancement of the alpha-elements (Mg, Si, and Ca) and low neutron-capture element (Sr, Ba, Eu) abundances supporting the classification of Cetus II as a likely UFD. The star exhibits lower Sc, Ti, and V abundances than Milky Way (MW) halo stars with similar metallicity. This signature is consistent with yields from a supernova (SN) originating from a star with a mass of ~11.2 solar masses. In addition, the star has a Potassium abundance of [K/Fe] = 0.81 which is somewhat higher than the K abundances of MW halo stars with similar metallicity, a signature which is also present in a number of UFD galaxies. A comparison including globular clusters (GC) and stellar stream stars suggests that high K is a specific characteristic for some UFD galaxy stars and can thus be used to help classify objects as UFD galaxies.
Comment: 15 pages, 7 figures, 5 tables, accepted to ApJ
Comment: 15 pages, 7 figures, 5 tables, accepted to ApJ