Stellar Contents of the Galactic Giant H II Region NGC 3603

[摘要] WepresentCCDUBVRIandHαphotometryforthestarburstclusterassociatedwiththegalacticgiantHIIregionNGC3603.Themeanreddeningoftheclustermemberscomesouttobe$$langleE(B-V)angle=1.48pm0.21$$(s.d.).Thesurfacedistributionofthereddeningshowsaradialvariationwithaminimumneartotheclustercenterandtwolocalmaximaatradii∼30″and∼70″.Ourphotometricdataindicateananomalousreddeninglawforthedustinsidetheclusterregion,andtheratioofthetotaltotheselectiveextinction,R,isfoundtobe∼4.3.Acomparisonoftheobservationalandintrinsiccolour-magnitudedigrams(CMDs)yieldsameandistancemodulusof(m–M)0=14.0,whichcorrespondstoadistanceof6.3±0.6kpc.Thisdistanceissmallerthanthoseobtainedinearlierworks(e.g.,7.2kpc,Melnicketal.1989,AAA49.132.013)butisingoodagreementwiththekinematicdistance(6.1±0.6kpc)recentlyreportedbyDePreeetal.(1999,AAA71.132.041).Theclustershowsalargeagespread,containingstarsasoldasuptoseveralMyr.However,themeanageoftheclusterisfoundtobe≤1Myr.Weestimateaminimumstarformationefficiencyof∼25%andagasremovaltimeofτ∼4.6Myr.

[学科分类] 天文学(综合)

[关键词] "open clusters: individual (NGC 3603)";"reddenning law";"stars: mass function"