Facial reconstruction

Search LJMU Research Online

Browse Repository | Browse E-Theses

Age as a Major Factor in the Onset of Multiple Populations in Stellar Clusters

Martocchia, S, Cabrera-Ziri, I, Lardo, C, Dalessandro, E, Bastian, N, Kozhurina-Platais, V, Usher, CG, Niederhofer, F, Cordero, M, Geisler, D, Hollyhead, K, Kacharov, N, Larsen, S, Li, C, Mackey, D, Hilker, M, Mucciarelli, A, Platais, I and Salaris, M (2017) Age as a Major Factor in the Onset of Multiple Populations in Stellar Clusters. Monthly Notices of the Royal Astronomical Society, 473 (2). pp. 2688-2700. ISSN 0035-8711

[img]
Preview
Text
Age as a Major Factor in the Onset of Multiple Populations in Stellar Clusters.pdf - Published Version

Download (46MB) | Preview

Abstract

It is now well established that globular clusters (GCs) exhibit star-to-star light-element abundance variations (known as multiple stellar populations, MPs). Such chemical anomalies have been found in (nearly) all the ancient GCs (more than 10 Gyr old) of our Galaxy and its close companions, but so far no model for the origin of MPs is able to reproduce all the relevant observations. To gain new insights into this phenomenon, we have undertaken a photometric Hubble Space Telescope survey to study clusters with masses comparable to that of old GCs, where MPs have been identified, but with significantly younger ages. Nine clusters in the Magellanic Clouds with ages between $\sim$ 1.5-11 Gyr have been targeted in this survey. We confirm the presence of multiple populations in all clusters older than 6 Gyr and we add NGC 1978 to the group of clusters for which MPs have been identified. With an age of $\sim$ 2 Gyr, NGC 1978 is the youngest cluster known to host chemical abundance spreads found to date. We do not detect evident star-to-star variations for slightly younger massive clusters ($\sim$ 1.7 Gyr), thus pointing towards an unexpected age dependence for the onset of multiple populations. This discovery suggests that the formation of MPs is not restricted to the early Universe and that GCs and young massive clusters share common formation and evolutionary processes.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA; astro-ph.SR
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 24 Oct 2017 11:10
Last Modified: 16 Sep 2018 18:09
DOI or Identification number: 10.1093/mnras/stx2556
URI: http://researchonline.ljmu.ac.uk/id/eprint/7350

Actions (login required)

View Item View Item