Properties Of The Youngest Protostars In Perseus, Serpens, And Ophiuchus

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dc.contributor.utaustinauthorEvans, Neal J.en_US
dc.creatorEnoch, Melissa L.en_US
dc.creatorEvans, Neal J.en_US
dc.creatorSargent, Anneila I.en_US
dc.creatorGlenn, Jasonen_US
dc.date.accessioned2016-04-28T19:33:16Z
dc.date.available2016-04-28T19:33:16Z
dc.date.issued2009-02en
dc.description.abstractWe present an unbiased census of deeply embedded protostars in Perseus, Serpens, and Ophiuchus, assembled by combining large-scale 1.1 mm Bolocam continuum and Spitzer Legacy surveys. We identify protostellar candidates based on their mid-infrared (mid-IR) properties, correlate their positions with 1.1 mm core positions from Enoch et al. in 2006 and 2007, and Young et al. in 2006, and construct well-sampled spectral energy distributions using our extensive wavelength coverage (lambda = 1.25-1100 mu m). Source classification based on the bolometric temperature yields a total of 39 Class 0 and 89 Class I sources in the three-cloud sample. We compare to protostellar evolutionary models using the bolometric temperature-luminosity diagram, finding a population of low-luminosity Class I sources that are inconsistent with constant or monotonically decreasing mass accretion rates. This result argues strongly for episodic accretion during the Class I phase, with more than 50% of sources in a "sub-Shu" (dM/dt < 10(-6)M(circle dot) yr(-1)) accretion state. Average spectra are compared to protostellar radiative transfer models, which match the observed spectra fairly well in Stage 0, but predict too much near-IR and too little mid-IR flux in Stage I. Finally, the relative number of Class 0 and Class I sources is used to estimate the lifetime of the Class 0 phase; the three-cloud average yields a Class 0 lifetime of 1.7 +/- 0.3 x 10(5) yr, ruling out an extremely rapid early accretion phase. Correcting photometry for extinction results in a somewhat shorter lifetime (1.1 x 10(5) yr). In Ophiuchus, however, we find very few Class 0 sources (N(Class0)/N(Class I) similar to 0.1-0.2), similar to previous studies of that cloud. The observations suggest a consistent picture of nearly constant average accretion rate through the entire embedded phase, with accretion becoming episodic by at least the Class I stage, and possibly earlier.en_US
dc.description.departmentAstronomyen_US
dc.description.sponsorshipNASA Origins NNG04GG24G, NNX07A72Gen_US
dc.description.sponsorshipNSF AST-9980846, AST-0206158en_US
dc.identifierdoi:10.15781/T2H51T
dc.identifier.Filename2009_02_perseusserpens.pdfen_US
dc.identifier.citationEnoch, Melissa L., Neal J. Evans II, Anneila I. Sargent, and Jason Glenn. "Properties of the youngest protostars in Perseus, Serpens, and Ophiuchus." The Astrophysical Journal, Vol. 692, No. 2 (Feb., 2009): 973.en_US
dc.identifier.doi10.1088/0004-637x/692/2/973en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/34722
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectinfrared: ismen_US
dc.subjectism: cloudsen_US
dc.subjectism: individual (perseus, serpens,en_US
dc.subjectophiuchus)en_US
dc.subjectstars: formationen_US
dc.subjectsubmillimeteren_US
dc.subjectspitzer c2d surveyen_US
dc.subjectdust continuum emissionen_US
dc.subjectmass star-formationen_US
dc.subjectmain-sequence evolutionen_US
dc.subjectauriga molecular clouden_US
dc.subjectt-tauri starsen_US
dc.subjectstellaren_US
dc.subjectobjectsen_US
dc.subjectinterstellar cloudsen_US
dc.subjectlegacy cloudsen_US
dc.subjectbolometric temperatureen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleProperties Of The Youngest Protostars In Perseus, Serpens, And Ophiuchusen_US
dc.typeArticleen_US

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