Obscured clusters III. Follow-up observations of Mercer 23

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Show simple item record Hanson, MM Kurtev, R Borissova, J Georgiev, L Ivanov, VD Hillier, DJ Minniti, D 2011-01-21T10:35:26Z 2011-01-21T10:35:26Z 2010
dc.identifier.issn 0004-6361
dc.identifier.uri http://hdlhandlenet/123456789/267
dc.description.abstract Context. New infrared surveys have revealed over 1000 new open cluster candidates in the MilkyWay, but these candidates need to be confirmed with follow up observations. Of particular interest are young, massive star clusters because they serve as nearby analogues to the distant super star clusters studied as point sources in other galaxies. Aims. We determine the physical parameters and investigate the high-mass stellar content of the infrared star cluster Mercer 23, situated near the Galactic plane (l = 53 degrees.772, b = + 0 degrees.164). Methods. Our analysis is based on new Baade/PANIC JHKS and ISAAC/VLT imaging of Mercer 23 and ISAAC/VLT moderate resolution (R approximate to 4000) spectroscopy of the brightest cluster members in the H-and K-bands. The cluster age is determined from isochrone main-sequence (MS) and pre-MS fitting. We derive stellar parameters for eight of the stellar members, using a full non-LTE modeling of the obtained spectra. Results. Mercer 23 is a very young cluster, with age of t = 2-4 Myr. The cluster suffers reddening of E(J-K-S) = 1.35, AV = 7.2 mag. The derived distance is d = 6.5 +/- 0.3 kpc. Our spectral modeling allows us to conclude that the three most luminous member are evolved highly massive stars: a WR star, and two mid-O supergiant stars, based on their derived luminosity. Conclusions. Mercer 23 is not a super-massive cluster such as those recently recognized to exist in the Milky Way. However, its mass estimate of 4-6 x 10(3) M-circle dot and possibly more, puts it in the class of young Galactic clusters hosting WR stars. en_US
dc.language.iso en en_US
dc.title Obscured clusters III. Follow-up observations of Mercer 23 en_US
dc.type Article en_US
dc.identifier.idprometeo 147
dc.identifier.doi 10.1051/0004-6361/200913122
dc.source.novolpages 516
dc.subject.wos Astronomy & Astrophysics
dc.description.index WoS: SCI, SSCI o AHCI
dc.subject.keywords Galaxy: open clusters and associations: general
dc.subject.keywords stars: Wolf-Rayet
dc.subject.keywords open clusters and associations: individual: [MCM2005b] 23
dc.relation.journal Astronomy & Astrophysics

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