  A jet from the low-mass YSO CB230-A had been discovered in NIR narrow-band
images. We aim to investigate the physical properties of the region from where
the jet is launched. Our analysis was carried out using low-resolution NIR
spectra acquired with the camera NICS at the TNG telescope, with JH and HK
grisms and a 1 arcsec-wide slit. These observational data were complemented
with infrared photometric data from the Spitzer space telescope archive. The
relevant physical properties of CB230-A were constrained by SED fitting of
fluxes from the NIR to the mm. The YSO spectrum exhibits a significant number
of atomic and molecular emission and absorption features. The characteristics
of this spectrum suggest that we are observing a region in the close vicinity
of CB230-A, i. e. its photosphere and/or an active accretion disk. The spectra
of the knots in the jet contain a large number of emission lines, including a
rich set of [FeII] lines. Emission due to H2 and [FeII] are not spatially
correlated, confirming that [FeII] and H2 are excited by different mechanisms,
in agreement with the models where [FeII] traces dissociative J-shocks and
molecular hydrogen traces slower C-shocks. By using intensity ratios involving
density-sensitive [FeII] lines, we estimated the electron densities in the jet
(6x10^3-1x10^4 cm^-3). This indicates either high density post-shock regions of
ionised gas or regions with a high degree of ionisation. By combining the
present data with previously obtained maps at NIR- and mm-wavelengths, the
emerging scenario is that CB230-A is a Class 0/I YSO driving an atomic jet that
is observed to be almost monopolar probably due to its inclination to the plane
of the sky and the resulting higher extinction of its red side. This jet
appears energetic enough to drive the molecular outflow observed in the mm.
