ar X iv : 0 70 8 . 13 65 v 1 [ as tr o - ph ] 1 0 A ug 2 00 7 Submillimeter arcsecond - resolution mapping of the highly collimated protostellar jet HH 211

We have mapped the protostellar jet HH 211 in 342 GHz continuum, SiO (J = 8− 7), and CO (J = 3− 2) emission at ∼ 1 resolution with the Submillimeter Array (SMA). Thermal dust emission is seen in continuum at the center of the jet, tracing an envelope and a possible optically thick compact disk (with a size < 130 AU) around the protostar. A knotty jet is seen in CO and SiO as in H2, but extending closer to the protostar. It consists of a chain of knots on each side of the protostar, with an interknot spacing of ∼ 2−3 or 600−900 AU and the innermost pair of knots at only ∼ 1 . 7 or 535 AU from the protostar. These knots likely trace unresolved internal (bow) shocks (i.e., working surfaces) in the jet, with a velocity range up to ∼ 25 km s. The two-sided mass-loss rate of the jet is estimated to be ∼ (0.7− 2.8)× 10 M⊙ yr . The jet is episodic, precessing, and bending. A velocity gradient is seen consistently across two bright SiO knots (BK3 and RK2) perpendicular to the jet axis, with ∼ 1.5±0.8 km s at ∼ 30±15 AU, suggesting a presence of a jet rotation. The launching radius of the jet, derived from the potential jet rotation, is ∼ 0.15−0.06 AU in the inner disk. Subject headings: stars: formation — ISM: individual: HH 211 — ISM: jets and outflows. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan; [email protected] 2 Harvard-Smithsonian Center for Astrophysics, Submillimeter Array, 645 North A’ohoku, Hilo, HI 96720 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 Laboratorio de Astrof́ısica Espacial y F́ısica Fundamental, INTA, Apartado 50727, E-28080 Madrid, Spain