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The effects of differential reddening and stellar rotation on the appearance of multiple populations in star clusters: The case of Trumpler 20

Platais, Imants; Melo, C; Quinn, S. N; Clem, J L; de Mink, S. E.; Dotter, Aaron; Kozhurina-Platais, V; Latham, D.W.; Bellini, A

Description

We present a detailed analysis of the upper main sequence of the 1.3 Gyr old open cluster Trumpler 20. High-accuracy BVI photometry combined with the Very Large Telescope/FLAMES medium-resolution spectroscopy of 954 stars is essential to understanding the unusual appearance of the color-magnitude diagram (CMD), initially suggesting multiple populations in Trumpler 20. We show that differential reddening is a dominant contributor to the apparent splitting/widening of the main-sequence turnoff...[Show more]

dc.contributor.authorPlatais, Imants
dc.contributor.authorMelo, C
dc.contributor.authorQuinn, S. N
dc.contributor.authorClem, J L
dc.contributor.authorde Mink, S. E.
dc.contributor.authorDotter, Aaron
dc.contributor.authorKozhurina-Platais, V
dc.contributor.authorLatham, D.W.
dc.contributor.authorBellini, A
dc.date.accessioned2015-12-13T22:40:07Z
dc.identifier.issn2041-8205
dc.identifier.urihttp://hdl.handle.net/1885/78093
dc.description.abstractWe present a detailed analysis of the upper main sequence of the 1.3 Gyr old open cluster Trumpler 20. High-accuracy BVI photometry combined with the Very Large Telescope/FLAMES medium-resolution spectroscopy of 954 stars is essential to understanding the unusual appearance of the color-magnitude diagram (CMD), initially suggesting multiple populations in Trumpler 20. We show that differential reddening is a dominant contributor to the apparent splitting/widening of the main-sequence turnoff region. At its extreme, the excess differential reddening reaches Δ(B - V) 0.1 while the adopted minimum reddening for the cluster is E(B - V) = 0.36. A unique sample of measured projected rotational velocities indicates that stellar rotation is high near the main-sequence turnoff, reaching vsin i 180 km s-1. By dividing the upper main-sequence stars into two equal groups of slow and fast rotators, we find that fast rotators have a marginal blueshift of δ(V - I) -0.01, corresponding to a difference in the median vsin i of 60 km s-1 between these subsamples. We conclude that stellar rotation has an insignificant effect on the morphology of the upper main sequence of this intermediate-age open cluster. Trumpler 20 appears to contain a single coeval population of stars but there is evidence that the red clump is extended.
dc.publisherInstitute of Physics Publishing Ltd.
dc.sourceAstrophysical Journal Letters
dc.subjectKeywords: open clusters and associations: general; open clusters and associations: individual (Trumpler 20); stars: rotation; techniques: spectroscopic
dc.titleThe effects of differential reddening and stellar rotation on the appearance of multiple populations in star clusters: The case of Trumpler 20
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume751
dc.date.issued2012
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationf5625xPUB6778
local.type.statusPublished Version
local.contributor.affiliationPlatais, Imants, Johns Hopkins University
local.contributor.affiliationMelo, C, European South Observatory
local.contributor.affiliationQuinn, S. N, Harvard-Smithsonian Center for Astrophysics
local.contributor.affiliationClem, J L, Department of Physics and Astronomy
local.contributor.affiliationde Mink, S. E., Universiteit Utrecht
local.contributor.affiliationDotter, Aaron, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationKozhurina-Platais, V, Space Telescope Science Institute
local.contributor.affiliationLatham, D.W., Harvard University
local.contributor.affiliationBellini, A, Space Telescope Science Institute
local.description.embargo2037-12-31
local.bibliographicCitation.issue1
local.identifier.doi10.1088/2041-8205/751/1/L8
dc.date.updated2016-02-24T09:31:06Z
local.identifier.scopusID2-s2.0-84860762032
CollectionsANU Research Publications

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