NIR spectroscopic survey of protostellar jets in the star forming region IC 1396N
Journal
Date Issued
2022
Author(s)
Abstract
Abridged. The bright-rimmed cloud IC1396N hosts CO, H$_2$, and Herbig-Haro
outflows powered by millimetre compact sources. We aim to characterise the
kinematics and physical conditions of the H$_2$ emission features spread over
IC1396N, which appear as chains of knots with a jet-like morphology, tracing
different H$_2$ outflows, and to obtain further information about (and an
identification of) the driving sources. Low-resolution, long-slit near-infrared
spectra were acquired with NICS at the TNG, using grisms KB (R~1200), HK and JH
(R~500). Several slit pointings and PA were used throughout IC1396N to sample a
number of the H$_2$ knots previously detected in deep H$_2$ 2.12 $\mu$m images.
The knots exhibit rich ro-vibrational spectra of H$_2$, consistent with
shock-excited excitation, from which radial velocities and relevant physical
conditions of the IC1396N H$_2$ outflows were derived. These also allowed
estimating extinction ranges towards several features. [FeII] emission was only
detected towards a few knots, which also display unusually large H$_2$ 1-0
S(3)/S(1) flux ratios. The obtained radial velocities confirm that most of the
outflows are close to the plane of the sky. Nearby knots in the same chain
often display different radial velocities, both blue-shifted and red-shifted,
which we interpret as due to ubiquitous jet precession in the driving sources
or the development of oblique shocks. One of the chains (strand A) appears as a
set of features trailing a leading bow-shock structure consistent with the
results of 3-D magneto-hydrodynamical models. Either side of the leading
bow-shock (A15) exhibits a different radial velocity, whose possible
explanations are discussed in the paper. Our data cannot confirm whether
strands A and B have both been originated by the intermediate mass young
stellar object BIMA 2.
Volume
664
Start page
A11
Issn Identifier
0004-6361
Ads BibCode
2022A&A...664..A11M
Rights
open.access
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