2010ApJ...710.1786Y

We have performed detailed imaging and analyses of the Submillimeter Array observation in 230 GHz continuum, ¹²CO (2-1), ¹³CO (2-1), and C¹⁸O (2-1) emissions toward B335, an isolated and nearby (∼150 pc) Bok globule with an embedded Class 0 source (L_bol∼ 1.5 L_☉). We report the first discovery of high-velocity (V_propagation∼ 160 km/s) ¹²CO (2-1) jets with a size of ∼900x1500 AU along the east-west direction in B335. The estimated mass-loss rate (∼2.3x10^–7 M_☉/yr) and the momentum flux (∼3.7x10^–5 M_☉/yr km/s) of the ¹²CO jets in B335 are one order of magnitude lower than those of other ¹²CO jets in more luminous sources such as HH 211 (L_bol∼ 3.6 L_☉) and HH 212 (L_bol ∼ 14 L_☉). The weaker jet activity in B335 could be due to the lower active accretion onto the central protostar. The C¹⁸O emission shows a compact (∼1500 AU) condensation associated with the central protostar, and it likely traces the protostellar envelope around B335, as in the case of the 230 GHz continuum emission. The envelope exhibits a velocity gradient from the east (blueshifted) to west (redshifted) that can be interpreted as an infalling motion. The estimated central stellar mass, the mass infalling rate, and the accretion luminosity are 0.04 M_☉, 6.9x10^–6 M_☉/yr, and 2.1 L_☉, respectively. On the other hand, there is no clear velocity gradient perpendicular to the outflow axis in the C¹⁸O envelope, suggesting little envelope rotation on a few hundred AU scale. The upper limits of the rotational velocity and specific angular momentum were estimated to be 0.04 km/s and 7.0x10^–5 km/s pc at a radius of 370 AU, respectively. The specific angular momentum and the inferred Keplerian radius (∼6 AU) in B335 are one to two orders of magnitude smaller than those in other more-evolved sources. Possible scenarios to explain the lower specific angular momentum in B335 are discussed.