Kinematics of the L1551 Jet

The velocity structure of the L 1551 jet in [S II] 6731. North is to the right and east is up. The jet moves to the WSW away from the IRS 5, which is located off the field of view to the upper right in each frame. Labels on the individual knots follow the nomenclature of Stocke etal (1988). The color composites were made by loading images of a specified range of radial velocities (labeled by R, G, and B in km/s with respect to L 1551 in the figure) into the red, green, and blue channels, respectively. Equal intensities of red and green produce yellow, while equal amounts of red, green and blue give white.

Left: Two overviews of the region with differing color representations of the velocity fields. The data show that the two jets imaged by FL98 have markedly dissimilar radial velocities. Right: Two composites of the bright jet that show a sharp deceleration of jet material as it enters knot #3. The white area in the top right frame marks the region with the largest emission line width. An area of slower blueshifted material that precedes the bow shock appears as a reddish halo surrounding the brightest emission in these composites.