Gas and Dust Condensations and a Peculiar Class 0 Object in the Lupus 3 Star‐Forming Cloud

Abstract

The Lupus 3 molecular cloud has been surveyed for dense gas and dust cores and embedded objects in radio [H 13 CO + J ¼ 1Y0 line and 1.2 mm continuum] and infrared [JHKsL 0 MN1 bands and H2 v ¼1Y0 S(1) line] wavelengths. These observations unveil a filamentary cloud, three dense cores, an embedded millimeter-wave source (MMS),andanassociatedelongatedobjectintheKband.ThepropertiesofthethreedensecoresareM ¼ 3:5Y5:6 M� , R ¼ 0:04Y0:06pc,andn(H2) ¼ (1:0Y3:9) ; 10 5 cm � 3 ,propertiessimilartothoseinTaurus.Twoofthesethreeobjects are likely to be prestellar cores, while the other one exhibits ongoing star formation. The spectral energy distribution (SED) analysis of the MMS shows that it is a remarkably cold Class 0 object with molecular outflow detected in the CO(J ¼ 3Y2) line and peculiar near-IR detections. From the estimated low bolometric temperature (39.5 K), faint bolometric luminosity (0.16 L� ), and sufficiently large envelope mass (0.52 M� ), the MMS is expected to be in a very earlyphase(� 10 4 yr)ofmassaccretion.TheK-bandelongatedfeatureappearstobescatteredlightoriginatingfromthe embeddedcentral objectofthe MMS seenthrough the outflowcavityopening towardHH 78onthe nearsideasshown by the blueshifted CO wings. The MMS has also been detected by the Spitzer Space Telescope, and its near-IR images exhibit butterfly-shaped nebulosity emission as scattered light through the bipolar cavities in contrast to that in the K band. Together with the Spitzer and NTT JHK photometric data, the observed SED has a short-wavelength cutoff suggesting a low effective temperature (<1400 K) of the central object. Subject headingg dust, extinction — ISM: clouds — ISM: individual (Lupus cloud) — ISM: jets and outflows — stars: formation — stars: preYmain-sequence