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| Paper: |
Star Formation in NGC 2068, NGC 2071, and Northern L1630 |
| Monograph: |
4, Handbook of Star Forming Regions:
Volume I, The Northern Sky |
| Page: |
693 |
| Authors: |
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| Abstract: |
The L 1630 giant molecular cloud in Orion is a well-studied region of star formation. This review summarizes the main properties of the molecular cloud, describing its structure and appearance at various wavelengths; the major centres of star formation in the northern half of the cloud are reviewed and discussed, and descriptions given of the main individual sources of particular interest. An examination of distance estimates yields a mean value of ∼400 pc to L 1630, although values of 390 to 415 pc may be more applicable to the north and south ends of the cloud, respectively. The cloud is elongated, and has two well-defined centres of ongoing star formation, each of which is in turn composed of 2 or 3 regions of active star formation: NGC 2071, NGC 2068, HH24–26, NGC 2023 and NGC 2024. Detailed studies of these regions have revealed sources at all stages of pre-main sequence evolution from Class 0 protostars to T Tauri stars. The majority of such sources in northern L 1630 are of low luminosity (less than ∼100 L⊙). The recent outburst from IRAS 05436−0007 (V1647 Ori) has attracted much attention, and appears to be a low-luminosity protostar, perhaps in a transition phase from Class I to Class II. The diffuse ionized region known as Barnard’s Loop crosses the face of the cloud but does not appear to be interacting dynamically with L 1630. |
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