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A general abundance problem for all self-enrichment scenarios for the origin of multiple populations in globular clusters

Bastian, N and Cabrera-Ziri, I and Salaris, M (2015) A general abundance problem for all self-enrichment scenarios for the origin of multiple populations in globular clusters. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 449 (3). pp. 3333-3346. ISSN 0035-8711

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Abstract

A number of stellar sources have been advocated as the origin of the enriched material required to explain the abundance anomalies seen in ancient globular clusters (GCs). Most studies to date have compared the yields from potential sources (asymptotic giant branch stars (AGBs), fast rotating massive stars (FRMS), high mass interacting binaries (IBs), and very massive stars (VMS)) with observations of specific elements that are observed to vary from star-to-star in GCs, focussing on extreme GCs such as NGC 2808, which display large He variations. However, a consistency check between the results of fitting extreme cases with the requirements of more typical clusters, has rarely been done. Such a check is particularly timely given the constraints on He abundances in GCs now available. Here we show that all of the popular enrichment sources fail to reproduce the observed trends in GCs, focussing primarily on Na, O and He. In particular, we show that any model that can fit clusters like NGC 2808, will necessarily fail (by construction) to fit more typical clusters like 47 Tuc or NGC 288. All sources severely over-produce He for most clusters. Additionally, given the large differences in He spreads between clusters, but similar spreads observed in Na–O, only sources with large degrees of stochasticity in the resulting yields will be able to fit the observations. We conclude that no enrichment source put forward so far (AGBs, FRMS, IBs, VMS - or combinations thereof) is consistent with the observations of GCs. Finally, the observed trends of increasing [N/Fe] and He spread with increasing cluster mass cannot be resolved within a self-enrichment framework, without further exacerbating the mass budget problem.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record "A general abundance problem for all self-enrichment scenarios for the origin of multiple populations in globular clusters", MNRAS, v.449(3) is available online at: http://dx.doi.org/10.1093/mnras/stv543
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 26 Jun 2015 11:03
Last Modified: 07 Sep 2017 22:12
DOI or Identification number: 10.1093/mnras/stv543
URI: http://researchonline.ljmu.ac.uk/id/eprint/1461

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