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Simple stellar population models as probed by the Large Magellanic Cloud star cluster ESO 121-SC03

Xin, Yi; Deng, L; de Grijs, R; Mackey, Alasdair; Han, Z.W

Description

The presence of blue straggler stars (BSs) in star clusters has proven a challenge to conventional simple stellar population (SSP) models. Conventional SSP models are based on the evolution theory of single stars. Meanwhile, the typical locations of BSs in the colour-magnitude diagram of a cluster are brighter and bluer than the main-sequence turn-off point. Such loci cannot be predicted by single-star evolution theory. However, stars with such properties contribute significantly to the...[Show more]

dc.contributor.authorXin, Yi
dc.contributor.authorDeng, L
dc.contributor.authorde Grijs, R
dc.contributor.authorMackey, Alasdair
dc.contributor.authorHan, Z.W
dc.date.accessioned2015-12-10T23:00:44Z
dc.date.available2015-12-10T23:00:44Z
dc.identifier.issn0035-8711
dc.identifier.urihttp://hdl.handle.net/1885/61475
dc.description.abstractThe presence of blue straggler stars (BSs) in star clusters has proven a challenge to conventional simple stellar population (SSP) models. Conventional SSP models are based on the evolution theory of single stars. Meanwhile, the typical locations of BSs in the colour-magnitude diagram of a cluster are brighter and bluer than the main-sequence turn-off point. Such loci cannot be predicted by single-star evolution theory. However, stars with such properties contribute significantly to the integrated light of the cluster. In this paper, we reconstruct the integrated properties of the Large Magellanic Cloud cluster European Southern Observatory (ESO) 121-SC03, the only cluster populating the well-known age gap in the cluster age distribution, based on a detailed exploration of the individual cluster stars, and with particular emphasis on the cluster's BSs. We find that the integrated light properties of ESO 121-SC03 are dramatically modified by its BS component. The integrated spectral energy distribution (ISED) flux level is significantly enhanced towards shorter wavelengths, and all broad-band colours become bluer. When fitting the fully integrated ISED of this cluster based on conventional SSP models, the best-fitting values of age and metallicity are significantly underestimated compared to the true cluster parameters. The age underestimate is ∼40 per cent if we only include the BSs within the cluster's half-light radius and ∼60 per cent if all BSs are included. The corresponding underestimates of the cluster's metallicity are ∼30 and ∼60 per cent, respectively. The populous star clusters in the Magellanic Clouds are ideal objects to explore the potential importance of BSs for the integrated light properties of more distant unresolved star clusters in a statistically robust manner, since they cover a large range in age and metallicity.
dc.publisherBlackwell Publishing Ltd
dc.sourceMonthly Notices of the Royal Astronomical Society
dc.subjectKeywords: Blue stragglers; Galaxies: star clusters; Globular clusters: individual: ESO 121-SC03; Magellanic Clouds
dc.titleSimple stellar population models as probed by the Large Magellanic Cloud star cluster ESO 121-SC03
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume384
dc.date.issued2008
local.identifier.absfor020100 - ASTRONOMICAL AND SPACE SCIENCES
local.identifier.ariespublicationU3488905xPUB614
local.type.statusPublished Version
local.contributor.affiliationXin, Yi, Department of Physics and Astronomy
local.contributor.affiliationDeng, L, National Astronomical Observatories
local.contributor.affiliationde Grijs, R, University of Sheffield
local.contributor.affiliationMackey, Alasdair, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationHan, Z.W, Chinese Academy of Sciences
local.bibliographicCitation.issue1
local.bibliographicCitation.startpage410
local.bibliographicCitation.lastpage419
local.identifier.doi10.1111/j.1365-2966.2007.12720.x
dc.date.updated2015-12-10T08:23:11Z
local.identifier.scopusID2-s2.0-38749092215
CollectionsANU Research Publications

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