학술논문
Chemical Analysis of the Brightest Star of the Cetus II Ultrafaint Dwarf Galaxy Candidate
Document Type
article
Author
K. B. Webber; T. T. Hansen; J. L. Marshall; J. D. Simon; A. B. Pace; B. Mutlu-Pakdil; A. Drlica-Wagner; C. E. Martínez-Vázquez; M. Aguena; S. S. Allam; O. Alves; E. Bertin; D. Brooks; A. Carnero Rosell; J. Carretero; L. N. da Costa; J. De Vicente; P. Doel; I. Ferrero; D. Friedel; J. Frieman; J. García-Bellido; G. Giannini; D. Gruen; R. A. Gruendl; S. R. Hinton; D. L. Hollowood; K. Honscheid; K. Kuehn; J. Mena-Fernández; F. Menanteau; R. Miquel; R. L. C. Ogando; M. E. S. Pereira; A. Pieres; A. A. Plazas Malagón; E. Sanchez; B. Santiago; J. Allyn Smith; M. Smith; E. Suchyta; G. Tarle; C. To; N. Weaverdyck; B. Yanny
Source
The Astrophysical Journal, Vol 959, Iss 2, p 141 (2023)
Subject
Language
English
ISSN
1538-4357
Abstract
We present a detailed chemical abundance analysis of the brightest star in the ultrafaint 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 α -elements (Mg, Si, and Ca) and low neutron-capture element (Sr, Ba, and 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 originating from a star with a mass of ∼11.2 M _⊙ . 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 that is also present in a number of UFD galaxies. A comparison including globular clusters and stellar stream stars suggests that high K is a specific characteristic of some UFD galaxy stars and can thus be used to help classify objects as UFD galaxies.