HIERARCHICAL FRAGMENTATION AND JET-LIKE OUTFLOWS IN IRDC G28.34+0.06: A GROWING MASSIVE PROTOSTAR CLUSTER
- Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)
We present Submillimeter Array (SMA) {lambda} = 0.88 mm observations of an infrared dark cloud G28.34+0.06. Located in the quiescent southern part of the G28.34 cloud, the region of interest is a massive (>10{sup 3} M{sub sun}) molecular clump P1 with a luminosity of {approx}10{sup 3} L{sub sun}, where our previous SMA observations at 1.3 mm have revealed a string of five dust cores of 22-64 M{sub sun} along the 1 pc IR-dark filament. The cores are well aligned at a position angle (P.A.) of 48 deg. and regularly spaced at an average projected separation of 0.16 pc. The new high-resolution, high-sensitivity 0.88 mm image further resolves the five cores into 10 compact condensations of 1.4-10.6 M{sub sun}, with sizes of a few thousand AU. The spatial structure at clump ({approx}1 pc) and core ({approx}0.1 pc) scales indicates a hierarchical fragmentation. While the clump fragmentation is consistent with a cylindrical collapse, the observed fragment masses are much larger than the expected thermal Jeans masses. All the cores are driving CO (3-2) outflows up to 38 km s{sup -1}, the majority of which are bipolar, jet-like outflows. The moderate luminosity of the P1 clump sets a limit on the mass of protostars of 3-7 M{sub sun}. Because of the large reservoir of dense molecular gas in the immediate medium and ongoing accretion as evident by the jet-like outflows, we speculate that P1 will grow and eventually form a massive star cluster. This study provides a first glimpse of massive, clustered star formation that currently undergoes through an intermediate-mass stage.
- OSTI ID:
- 21576529
- Journal Information:
- Astrophysical Journal, Vol. 735, Issue 1; Other Information: DOI: 10.1088/0004-637X/735/1/64; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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