Accretion in Gravitationally Contracting Clouds

Publications of the Astronomical Society of Japan

Tomisaka, Kohji¹ 

[1] Faculty of Education, Niigata University, 2-8050 Ikarashi, Niigata 950-21 E-mail:

关键词: Accretion;    "Interstellar: clouds";    "Interstellar: medium";    Magnetohydrodynamics;    "Stars: formation";   

DOI  :  10.1093/pasj/48.5.L97

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Accretionflowinacontractingmagnetizedisothermalcloudwasstudiedusingmagnetohydrodynamicalsimulationsandanestedgridtechnique.First,theinterstellarmagnetizedcloudexperiencesa“runawaycollapse”phase,inwhichthecentraldensityincreasesdrasticallywithinafinitetimescale.Finally,itentersanaccretionphase,inwhichinflowingmatteraccretesontoacentralhigh-densitydiskoranew-bornstar.Wefoundthattheaccretionratereaches(4–40)×cs3/G,wherecsandGrepresenttheisothermalsoundspeedandthegravitationalconstant,respectively.Thisismuchlargerthanthestandardaccretionrateof0.975cs3/Gforahydrostaticisothermalsphericalcloud(Shu1977,AAA19.065.044).Duetotheeffectofanextrainfallvelocityachievedintherunawayphase(∼2cs),theaccretionrateisboosted.ThisratedeclineswithtimeincontrasttoShu'ssolution,butkeeps≳2.5cs3/G.Theobservedgasinfallratearoundproto-starssuchasL1551IRS5andHLTauisalsodiscussed.

【 授权许可】

Unknown