DisentanglingComplexMassiveStarFormingRegion
Tien-HaoHsieh(ASIAA)
Collaboration:MichihiroTakami(ASIAA)MitsuhikoHonda(KurumeUniversity)HiranoNoami(ASIAA)Sheng-YuanLiu(ASIAA)Yu-NungSu(ASIAA)YoshikoOkamoto(IbarakiUniversity)
Collaborationwelcome!
Low-massstarformation
Questionstohigh-massstarformation
• Howthematerialinfallsfromenvelope?– Problem:MBE=1.18Cthermal
3/(G3ρ)0.5
– Solution:CompetitiveaccretionorCoreaccretion?
• Howmassaccretesontothestar?– Accretionstopsat16Msun
– candiskaccretionsolveit?
Turbulentcoreaccretionvs.Competitiveaccretion
Credit:J.Tan,N.Wright
Challengesinstudyingmassivestarformation
Highlyobscured(Av∽100-1000)
Needlongerwavelengthmid-infraredtosubmm!
Largedistance(d≳2kpc)Crowded(104starsperpc3)
Needhighspatialresolutionobservation!
Infrareddiagnose-COMICSimaging
Howthemassiveprotostarsareclustered?
deWitetal.(2018)
COMICS24.6um
COMICS:high-resolution7.8,9.7,12.4,and24.6umimages
Infrareddiagnose-COMICSimaging
Howthemassiveprotostarsareclustered?
COMICS24.6um
COMICS:high-resolution7.8,9.7,12.4,and24.6umimages
DerivedAvmapfromsilicateabsorption!->dereddenedSEDs
SpectraltypeoftheHMprotostar(s)
Okamotoetal.(2003)
�PAH7.7,8.6,11.2,and12.7um~6eV[NeII]12.8um>22eV[ArIII]8.99um>28eV[SIV]10.51um>35eV
COMICSimagingorspectroscopy->DisentanglingthecompositionsofHMprotostars!
COovertoneemission
innerdisktracer?
Ileeetal.2013,2018
IRCSspectroscopy-DiskAccretion?
Bγasanaccretiontracer?
Butcouldalsofromoutflows!
Summary • Massivestarformationispoorlyunderstood!– Massinfall:competitiveaccretionorturbulentcore
• Infrareddiagnose:– COMICSimaging/spectroscopy
• Resolvetheclustermembers• ObtaintheforegroundAvmaps• IdentifyspectraltypesfromPAH,[NeII],[ArIII]and,[SIV]emission
– IRCSspectroscopy• CO(2—0)and(3—1)tracinghotgasfrominnerdisk• Brasaccretiontracer?
ThestellarpropertiesoftheHMprotostar
COMICSimagingorspectroscopy• Comparethespectraltypeswiththeagesofclustermemberslow-massstarorhigh-massstarformearlier?->CompetitiveaccretionorCoreaccretion
DiskAccretion?
IRTFsurveyCOisdetectedinonesourceoutof11 W33A-MM1
Ileeetal.2018
Withtheevolutionaryindicators,canwefindwhentheaccretionishalted?
DiskAccretion?
IRTFsurveyCOisdetectedinonesourceoutof11 W33A-MM1
Ileeetal.2018
Withtheevolutionaryindicators,canwefindwhentheaccretionishalted?
Diskaccretiontotheradiationpressureproblem
Krumholz+2009
Diskaccretiontotheradiationpressureproblem
�Sànchez-Mongeetal.(2013)
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