Astrometry of H$_2$O Masers in Nearby Star-Forming Regions with VERA I. IRAS 16293$-$2422 in $ho$ Oph East

[摘要] Wereportonresultsofmulti-epochVLBIobservationsofH$$_2$$Omasersassociatedwithalow-massyoungstellarobject,IRAS16293$$-$$2422in$$ho$$OphEast,andafringe-phaseandpositionreferencesource,ICRFJ162546.8$$-$$252738,usingtheVLBIExplorationofRadioAstrometry(VERA)forhigh-precisionastrometry.Weobtainedanannualparallaxofamaserfeaturetobe$$pi=$$5.6$$^{+1.5}_{-0.5}$$mas,correspondingtoadistanceof$$D=178^{+18}_{-37}$$pc.Wealsofound10relativepropermotionsofmaserfeatureswithrespecttothemaserfeaturementionedabove.Themotionoftheaccompanyingyoungstellarobject(YSO)hasalreadybeenfoundinthermalcontinuumemissionpreviouslyobservedwiththeVeryLargeArray.TheintrinsicmotionsofmasershavebeenestimatedfromtherelativepropermotionsaftertheYSO’smotionissubtractedfrom,andasystemicsecularmotionofthepositionreferencefeatureisaddedtothepropermotionsoriginallymeasured.Theintrinsicmaserkinematicalstructuremaytraceabipolaroutflow.

[学科分类] 天文学(综合)

[关键词] astrometry;masers;"stars: formation";"stars: individual (IRAS 16293–2422)";"ISM: jets and outflows"