Protostars in Perseus: Outflow‐induced Fragmentation

Autor: Derek Ward-Thompson, JoAnn O'Linger, Philippe André, Mary Barsony
Rok vydání: 1998
Předmět:
Zdroj: The Astrophysical Journal. 509:733-748
ISSN: 1538-4357
0004-637X
Popis: We present new far-infrared, submillimeter, and millimeter images of candidate protostars in the Perseus molecular cloud complex: L1448N/IRS3, L1448C, and IRAS 03282+3035. L1448N/IRS3 is now known to comprise three separate millimeter-continuum sources: L1448N(A) and L1448N(B), which form a close (7'' separation) binary, and L1448NW, ~20'' to the northwest. The new maps presented here include 12, 25, 60, and 100 μm high-resolution-processed (HIRES-processed) IRAS images, 450 and 800 μm maps from the 15 m James Clerk Maxwell Telescope (JCMT), and a 1300 μm bolometer array map of the L1448 sources from the IRAM 30 m telescope. We present new spectral energy distributions (SEDs) for L1448C, L1448NW, and IRAS 03282. We confirm the Class 0 status of L1448C, L1448N(A), L1448N(B), and IRAS 03282. There is evidence for a modest compact "disk" component in L1448C (~0.004 M☉). We deduce that a 1.4 M☉ circumbinary envelope surrounds the ~1 M☉ protobinary system, L1448N(A) + L1448N(B). The dust emission from IRAS 03282 is found to be somewhat extended, on scales of 0.015-0.03 pc. Extensive HIRES-processed point-source modeling of the 100 μm emission associated with IRAS 03282 reveals an elongated structure along a north-south axis, spatially coincident with the previously mapped NH3 (1, 1) emission. Both the 100 μm dust emission and the ammonia trace the dense core from which IRAS 03282 is currently forming. We identify two distinct outflows in L1448N for the first time, one powered by L1448N(A) and the other by L1448N(B). A bridge of dust emission linking L1448C to L1448N is clearly evident in our HIRES-processed 100 μm map. This dust structure traces the surface where the L1448C and L1448N(A) outflows collide. Two new 100 μm emission peaks are found, one coinciding with HH 197, the other with an H2 bow-shock feature. Both 100 μm peaks are located at positions where the blueshifted L1448C jet is deflected. The luminosity radiated by the dust emission bridge is ~6.5 L☉, which is a new estimate for the instantaneous L1448C outflow mechanical luminosity. We find Lmech/Lbol ≥ 50% for all of the confirmed Perseus Class 0 sources for which outflow data are available from the literature. Thus, we confirm a high Lmech/Lbol as a new distinguishing characteristic of Class 0 outflows. The dynamical times for the L1448N(B) and L1448C outflows have been revised upward to 13,000 and 32,000 yr, respectively, based on the identification of L1448N(B) as the powering source of HH 196 and of L1448C as the driving source of HH 267. As a consequence, the outflow dynamical times now agree with the typical ages inferred for Class 0 sources. There is strong evidence for outflow-induced star formation in the L1448 cloud. Being older, the L1448C outflow has disrupted and fragmented the core that is now forming the younger L1448N(A) + L1448N(B) protobinary. The interaction of the L1448N(A) and L1448N(B) outflows, in turn, may have produced the L1448NW condensation.
Databáze: OpenAIRE
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