DATA ON ASTROPHYSICS DISCUSSED BY T.A. MOVSESSIAN AND COLLEAGUES

News of Science
February 14, 2010

"The kinematics of the HH 83 optical outflow, located in the L 1641
molecular cloud, are investigated. Observations were carried out with
the Fabry-Perot scanning interferometer on the 6-m telescope of the
Special Astrophysical Observatory," scientists in Armenia report.

"The H alpha emission line was scanned with a spectral resolution of
R = 8200. The radial velocity along the jet increases with distance
from the source, confirming previous results. It also shows lower
amplitude variations which are not correlated with intensity. Both the
spatial width of the jet as well as the FWHM of the H alpha emission
line in the jet tend to decrease with distance from the source. The
velocity field across the jet demonstrates a decrease from the center
to the edges as well as some evidence for a transverse velocity
gradient. The blue-shifted bow shock is separated spatially and
spectrally into two distinct features, divided by about 2 " and 250
km s(-1), accordingly. Evidence is provided that these split features
correspond to forward and reverse shocks caused by a rapid pressure
increase as the jet begins a new oblique impact on the surrounding
medium. Radial velocity variations lengthwise and transverse to the
jet axis are discussed. Linear extrapolation of the jet velocity up to
the location of the terminal shock region yields the radial velocity
of the reverse jet shock," wrote T.A. Movsessian and colleagues.

The researchers concluded: "The data are consistent with an abrupt
outburst about one thousand years ago which ejected material with
total speeds of up to 400 km s(-1)."

Movsessian and colleagues published their study in Astronomy &
Astrophysics (Herbig-Haro flows in 3D: the HH 83 jet. Astronomy &
Astrophysics, 2009;508(2):773-778).

For additional information, contact T.A. Movsessian, Byurakan Astrophys
Observ, Aragatsotn Reg 378433, Armenia.

The publisher’s contact information for the journal Astronomy
& Astrophysics is: EDP Sciences S a, 17, Avenue du Hoggar, PA
Courtaboeuf, BP 112, F-91944 les Ulis Cedex a, France.