The low-mass YSO CB230-A: investigating the protostar and its jet with NIR spectroscopy and Spitzer observations

Abstract

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.

arXiv comment14 pages, 7 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (23)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A grid of 200,000 YSO model SEDs
• An Infrared Spectroscopic Sequence of M, L and T Dwarfs
• Absolute Calibration of the Infrared Array Camera on the Spitzer Space Telescope
• The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low-Resolution Near-Infrared Spectra
• Infrared Spectra and Spectral Energy Distributions of Late-M- and L-Dwarfs
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• Spectral Energy Distributions for Disk and Halo M--Dwarfs
• Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. II. 70 micron Imaging
• Near-Infrared Spectral Classification of late-M and L Dwarfs
• Identifying Young Brown Dwarfs Using Gravity-Sensitive Spectral Features
• Which are the youngest protostars? Determining properties of confirmed and candidate Class0 sources by broad-band photometry
• Near-Infrared Classification Spectroscopy: H-band Spectra of Fundamental MK Standards
• A combined optical/infrared spectral diagnostic analysis of the HH1 jet
• Recipes for stellar jets: results of combined optical/infrared diagnostics
• The Physical Natures of Class I and Flat-Spectrum Protostellar Photospheres: A Near-Infrared Spectroscopic Study
• Tracing the Mass during Low-Mass Star Formation, IV: Observations and Modeling of the Submillimeter Continuum Emission from Class I Protostars
• Probing the embedded YSOs of the R CrA region through VLT-ISAAC spectroscopy
• OVRO N2H+ Observations of Class 0 Protostars: Constraints on the Formation of Binary Stars
• Near-Infrared Classification Spectroscopy: J-Band Spectra of Fundamental MK Standards
• SCUBA Mapping of Spitzer c2d Small Clouds and Cores
• Discovery of [FeII]- and H2-emission from protostellar jets in the CB3 and CB230 globules

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• SMA observations of the polarized dust emission in solar-type Class 0 protostars: the magnetic field properties at envelope scales
• Collisionless shocks in partly ionized plasma with cosmic rays: microphysics of non-thermal components
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