Kinematics of SiO J=8-7 Emission towards the HH 212 Jet

Abstract

We present SiO J=8-7 (347.3 GHz) observations towards HH 212 using the ASTE telescope. Our observations with a 22''-diameter beam show that the SiO emission is highly concentrated within 1' of the driving source. We carefully compare the SiO observations with archival H_2 1-0 S(1) images and published H_2 echelle spectra. We find that, although the SiO velocities closely match the radial velocities seen in H_2, the distribution of H_2 and SiO emission differ markedly. We attribute the latter to the different excitation conditions required for H_2 and SiO emission, particularly the higher critical density (n_H2 ~10^8 cm^-3) of the SiO J=8-7 emission. The kinematic similarities imply that the H_2 and SiO are associated with the same internal working surfaces. We conclude that the SiO J=8-7 emission has a potential to probe the jet/wind launching region through interferometric observations in the future, particularly for the youngest, most deeply embedded protostars where IR observations are not possible.

arXiv comment6 pages, 4 figures, accepted to PASJ

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Cited by in corpus (6)

• A highly-collimated SiO jet in the HH212 protostellar outflow
• HH 212: SMA Observations of a Remarkable Protostellar Jet
• A Detailed Study of Spitzer-IRAC Emission in Herbig-Haro Objects (I): Morphology and Flux Ratios of Shocked Emission
• New Distance and Revised Natures of High Mass Star Formation in G5.89-0.39
• A Detailed Study of Spitzer-IRAC Emission in Herbig-Haro Objects (II): Interaction Between Ejecta and Ambient Gas
• The Giant Herbig-Haro Flow HH 212 and Associated Star Formation