Online-Ressource | |
Verfasst von: | Hanke, Michael [VerfasserIn] |
Koch-Hansen, Andreas [VerfasserIn] | |
Titel: | Insights into the chemical composition of the metal-poor Milky Way halo globular cluster NGC 6426 |
Verf.angabe: | M. Hanke, A. Koch, C.J. Hansen, and A. McWilliam |
E-Jahr: | 2016 |
Jahr: | December 20, 2016 |
Umfang: | 14 S. |
Fussnoten: | Gesehen am 24.10.2017 |
Titel Quelle: | Enthalten in: De.arxiv.org |
Ort Quelle: | [S.l.] : Arxiv.org, 1991 |
Jahr Quelle: | 2016 |
Band/Heft Quelle: | (2016) Artikel-Nummer 1612.05989, 14 Seiten |
Abstract: | We present our detailed spectroscopic analysis of the chemical composition of four red giant stars in the halo globular cluster NGC 6426. We obtained high-resolution spectra using the Magellan2/MIKE spectrograph, from which we derived equivalent widths and subsequently computed abundances of 24 species of 22 chemical elements. For the purpose of measuring equivalent widths, we developed a new semi-automated tool, called EWCODE. We report a mean Fe content of [Fe/H] = -2.34$\pm$0.05 dex (stat.) in accordance with previous studies. At a mean $\alpha$-abundance of [(Mg,Si,Ca)/3 Fe] = 0.39$\pm$0.03 dex, NGC 6426 falls on the trend drawn by the Milky Way halo and other globular clusters at comparably low metallicities. The distribution of the lighter $\alpha$-elements as well as the enhanced ratio [Zn/Fe] = 0.39 dex could originate from hypernova enrichment of the pre-cluster medium. We find tentative evidence for a spread in the elements Mg, Si, and Zn, indicating an enrichment scenario, where ejecta of evolved massive stars of a slightly older population polluted a newly born younger one. The heavy element abundances in this cluster fit well into the picture of metal-poor globular clusters, which in that respect appear to be remarkably homogeneous. The pattern of the neutron-capture elements heavier than Zn point towards an enrichment history governed by the r-process with only little -if any- sign of s-process contributions. This finding is supported by the striking similarity of our program stars to the metal-poor field star HD 108317. |
URL: | Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt. Kostenfrei: Volltext: http://arxiv.org/abs/1612.05989 |
Datenträger: | Online-Ressource |
Sprache: | eng |
Sach-SW: | Astrophysics - Astrophysics of Galaxies |
K10plus-PPN: | 1564706982 |
Verknüpfungen: | → Sammelwerk |