Distance to Orion KL Measured with VERA

[摘要] WepresenttheinitialresultsofmultiepochVLBIobservationsof22GHzH$$_{2}$$OmasersintheOrionKLregionwithVERA(VLBIExplorationofRadioAstrometry).WiththeVERAdual-beamreceivingsystem,wecarriedoutphase-referencingVLBIastrometry,andsuccessfullydetectedtheannualparallaxofOrionKLtobe2.29$$;pm;$$0.10mas,correspondingtoadistanceof437$$;pm;$$19pcfromtheSun.ThedistancetoOrionKLwasdeterminedforthefirsttimewiththetrigonometricparallaxmethodintheseobservations.Althoughthisvalueisconsistentwiththatpreviouslyreported,480$$;pm;$$80pc,whichwasestimatedfromastatisticalparallaxmethodusingthepropermotionsandradialvelocitiesoftheH$$_{2}$$Omaserfeatures,ournewresultsprovideamuchmoreaccuratevaluewithanuncertaintyofonly4%.Inadditiontotheannualparallax,wedetectedanabsolutepropermotionofthemaserfeature,suggestinganoutflowmotionpoweredbytheradiosourceIalongwiththesystematicmotionofsourceIitself.

[学科分类] 天文学(综合)

[关键词] astrometry;"ISM: individual objects (Orion KL)";"ISM: jets and outflows";"masers (H2O)";"radio lines: ISM"