2011ApJ...742...57Y

We made C¹⁸O (2-1) and CS (7-6) images of the protostellar envelope around B335 with a high spatial dynamic range from ∼10,000 to ∼400 AU by combining the Submillimeter Array and single-dish data. The C¹⁸O emission shows an extended (∼10,000 AU) structure as well as a compact (∼1500 AU) component concentrated at the protostellar position. The CS emission shows a compact (∼900 AU) component surrounding the protostar, plus a halo-like (∼3000 AU) structure elongated along the east-west direction. At higher velocities (|ΔV| ≳ 0.3 km/s), the CS emission is stronger and more extended than the C¹⁸O emission. Physical conditions of the envelope were examined through a Large Velocity Gradient model. At|ΔV| ≳ 0.3 km/s, the gas temperature is higher (>40 K) than that at|ΔV| ≲ 0.3 km/s, whereas the gas density is lower (<10⁶/cm3). We consider that the higher temperature and lower density gas at|ΔV| ≳ 0.3 km/s is related to the associated outflow, while the lower temperature and higher density gas at|ΔV| ≲ 0.3 km/s is the envelope component. From the inspection of the positional offsets in the velocity channel maps, the radial profile of the specific angular momentum of the envelope rotation in B335 was revealed at radii from ∼10⁴ down to ∼10² AU. The specific angular momentum decreases down to a radius of ∼370 AU, and then appears to be conserved within that radius. A possible scenario of the evolution of envelope rotation is discussed.