Dust Continuum Imaging of the HH 24 Region in L1630

Open Access
Publisher Website
Google Scholar
Abstract
We have mapped the 1300 and 350 μm continuum emission in the region surrounding the Herbig-Haro objects HH 22-HH 26 in L1630, which is part of the Orion B molecular cloud complex, using the MPIR bolometer at the IRAM 30 m telescope and the SHARC bolometer camera at the Caltech Submillimeter Observatory (CSO). Our observations reveal the presence of a cluster of at least nine protostellar condensations at various evolutionary stages in the region around HH 24-HH 26. In addition to two previously identified class 0 protostars, two additional sources with a low 350/1300 μm flux ratio are detected. Although the lack of far-infrared fluxes precludes a definitive determination of their nature, their low 350/1300 μm flux ratio along with the absence of embedded infrared and radio continuum sources suggests that they are likely to be in a very early evolutionary stage. In particular, one of these two sources appears quite compact in the 1300 μm image and may be in the short-lived phase of isothermal collapse. In addition, we have detected three millimeter continuum sources in the vicinity of the HH 22-HH 23 objects, including a compact source at the origin of the HH 23 optical jet. The bolometric luminosity, submillimeter-to-bolometric luminosity ratio, temperature, and mass of this source are all consistent with those of a class 0 protostar. However, the compactness of the source suggests that the continuum emission may be dominated by an unresolved disk, as would be expected for a more evolved protostellar source. No evidence is found for the presence of a molecular outflow associated with this source in our CO, 13CO, and HCO+ data obtained with the CSO.