High‐Resolution Wide‐Field Imaging of Star‐forming Regions in NGC 1333

Abstract

BIMA Interferometer observations of dust continuum emission at 1.3 mm probe protostellar disk and envelope structures of the two brightest millimeter sources near SVS 13, from 0 .3 to 20 . The SVS 13 ridge is the site of a small group of deeply embedded protostars in NGC 1333 that are thought to be forming solar-type stars. Powerful molecular outflows suggest these sources are still engaged in the mass accretion process and may have substantial regions surrounding the central sources undergoing infall. High-resolution 1.3 mm data in conjunction with a previously published single-dish map at 1.3 mm (R. Chini et al. 1997, AA S. Terebey, F. H. Shu, & P. Cassen 1984, ApJ, 286, 529) that defines the division between collapse and quasi-static regions in the envelope. Using a measured line width to trace the sound speed in combination with the inferred collapse radius verifies that these systems are very young, only ≈ yr old. 4 2.9 # 10 Growth of dust grains to ≈1 cm in these young protostellar disks is detected using millimeter-wave spectral index comparisons of the dust emission in the protostellar envelope and disk. These are the first observations to have high resolution and sensitivity to large-scale structures and to sample the disks and envelopes in the same system at 110 and 220 GHz (110 GHz observations from L. W. Looney, L. G. Mundy, & W. J. Welch 2000, ApJ, 529, 477). The observations demonstrate the dust-mass opacity spectral index for the compact strucb ≈ 0 tures (disks) around SVS 13A and B, whereas for the largescale envelopes, (defined by and , after b 2 b b ≈ 2 F ∝ n k ∝ n n n