The Dusty Silhouette Jet HH 1019 in the Carina Nebula
  We report the discovery in Hubble Space Telescope (HST) images of the new
Herbig-Haro jet, HH 1019, located near the Tr 14 cluster in the Carina Nebula.
Like other HH jets in the region, this bipolar collimated flow emerges from the
head of a dark dust pillar. However, HH 1019 is unique because -- unlike all
other HH jets known to date -- it is identified by a linear chain of dark,
dusty knots that are seen primarily in silhouette against the background screen
of the H II region. Proper motions confirm that these dark condensations move
along the jet axis at high speed. [S II] emission traces a highly collimated
jet that is spatially coincident with these dust knots. The high extinction in
the body of the jet suggests that this outflow has lifted a large amount of
dust directly from the disk, although it is possible that it has entrained dust
from its surrounding protostellar envelope before exiting the dust pillar. If
dust in HH 1019 originates from the circumstellar disk, this provides further
evidence for a jet launched from a range of radii in the disk, including those
outside the dust sublimation radius. HH 1019 may be the prototype for a new
subclass of dusty HH objects seen primarily in extinction against the
background screen of a bright H II region. Such jets may be common, but
difficult to observe because they require the special condition of a very
bright background in order to be seen in silhouette.
