HH 211 is a nearby young protostellar system with a highly collimated jet .
We have mapped it in 352 GHz continuum , SiO ( J = 8 - 7 ) , and HCO ^ { + } ( J = 4 - 3 ) emission at up to \sim 0 ^ { \prime \prime } _ { { } ^ { \textrm { . } } } 2 resolution with the Submillimeter Array ( SMA ) .
The continuum source is now resolved into two sources , SMM1 and SMM2 , with a separation of \sim 84 AU .
SMM1 is seen at the center of the jet , probably tracing a ( inner ) dusty disk around the protostar driving the jet .
SMM2 is seen to the southwest of SMM1 and may trace an envelope-disk around a small binary companion .
A flattened envelope-disk is seen in HCO ^ { + } around SMM1 with a radius of \sim 80 AU perpendicular to the jet axis .
Its velocity structure is consistent with a rotation motion and can be fitted with a Keplerian law that yields a mass of \sim 50 \pm 15 M _ { \textrm { \scriptsize Jup } } ( a mass of a brown dwarf ) for the protostar .
Thus , the protostar could be the lowest mass source known to have a collimated jet and a rotating flattened envelope-disk .
A small-scale ( \sim 200 AU ) low-speed ( \sim 2 km s ^ { -1 } ) outflow is seen in HCO ^ { + } around the jet axis extending from the envelope-disk .
It seems to rotate in the same direction as the envelope-disk and may carry away part of the angular momentum from the envelope-disk .
The jet is seen in SiO close to \sim 100 AU from SMM1 .
It is seen with a “ C-shaped ” bending .
It has a transverse width of \lesssim 40 AU and a velocity of \sim 170 \pm 60 km s ^ { -1 } .
A possible velocity gradient is seen consistently across its innermost pair of knots , with \sim 0.5 km s ^ { -1 } at \sim 10 AU , consistent with the sense of rotation of the envelope-disk .
If this gradient is an upper limit of the true rotational gradient of the jet , then the jet carries away a very small amount of angular momentum of \lesssim 5 AU km s ^ { -1 } and thus must be launched from the very inner edge of the disk near the corotation radius .