Skewed Distributions and Opposite Velocity Gradients of Submillimeter Molecular Lines in Low-Mass Protostellar Envelopes

Publications of the Astronomical Society of Japan

Takakuwa, Shigehisa²  Kamazaki, Takeshi¹ 

[1] Joint ALMA Observatory, Ave. Alonso de Cordova 3107, Vitacura, Santiago, Chile;Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan

关键词: "ISM: molecules";    "ISM: structure";    "stars: formation";    submillimeter;   

DOI  :  10.1093/pasj/63.4.921

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

WehavemademappingobservationsofL1551IRS5,L1551NE,L723,andL43andsingle-pointobservationsofIRAS16293$$-$$2422inthesubmillimeterCS($$J$$$$=$$7–6)andHCN($$J$$$$=$$4–3)lineswithAtacamaSubmillimeterTelescopeExperiment(ASTE).UsingthepresentdataandourpreviousASTEobservationsofL483andB335together,wefoundadefinitecorrelationbetweensourcebolometricluminositiesandtotalintegratedintensitiesofthesubmillimeterlines($$I_{mCS}$$$$propto$$$$L_{mbol}^{0.92}$$).ThecombinedASTE$$+$$SubmillimeterArrayCS(7–6)imageofL1551IRS5exhibitsanextended($$sim$$2000AU)componenttracingtheassociatedreflectionnebulaatwestandsouthwest,aswellasacompact($$lesssim$$500AU)componentcenteredontheprotostellarposition.ThepeaksoftheCSandHCNemissionsinL1551NEarenotlocatedattheprotostellarpositionbutoffset($$sim$$1400AU)towardtheassociatedreflectionnebulaatwest.Bystatisticalanalyses,weconfirmedthevelocitygradientsoftheCS(7–6)emissionthatareoppositetothoseofthemillimeterlinesalongtheoutflowdirection,whichwereportedinourearlypaper.Themagnitudesofthesubmillimetervelocitygradientsareestimatedtobe(9.7$$pm$$1.7)$$imes$$10$$^{-3}$$kms$$^{-1}$$arcsec$$^{-1}$$inL1551IRS5and(7.6$$pm$$2.4)$$imes$$10$$^{-3}$$kms$$^{-1}$$arcsec$$^{-1}$$inL483.Wesuggestthatthe“skewed”submillimetermolecularemissionstowardtheassociatedreflectionnebulaeatafewthousandAUscaletracethewarm($$gtrsim$$40K)wallsoftheenvelopecavities,excavatedbytheassociatedoutflowsanddirectlyirradiatedbythecentralprotostars.Theoppositevelocitygradientsalongtheoutflowdirectionlikelyreflectthedispersinggasmotionatthewallofthecavityinenvelopesperpendiculartotheoutflow.

【 授权许可】

Unknown