IGRINS Near-IR High-Resolution Spectroscopy of Multiple Jets around LkH$\alpha$ 234

Abstract

We present the results of high-resolution near-IR spectroscopy toward the multiple outflows around the Herbig Be star Lk{\Ha} 234 using the Immersion Grating Infrared Spectrograph (IGRINS). Previous studies indicate that the region around Lk{\Ha} 234 is complex, with several embedded YSOs and the outflows associated with them. In simultaneous H$-$ and K$-$band spectra from HH 167, we detected 5 {\FeII} and 14 H${}_2$ emission lines. We revealed a new {\FeII} jet driven by radio continuum source VLA 3B. Position-velocity diagrams of H${}_2$ 1$-$0 S(1) $\lambda$2.122 $\micron$ line show multiple velocity peaks. The kinematics may be explained by a geometrical bow shock model. We detected a component of H${}_2$ emission at the systemic velocity (V${}_{LSR}$ $=$ $-$10.2 {\kms}) along the whole slit in all slit positions, which may arise from the ambient photodissociation region. Low-velocity gas dominates the molecular hydrogen emission from knots A and B in HH 167, which is close to the systemic velocity, {\FeII} emission lines are detected at farther from the systemic velocity, at V${}_{LSR}$ $=$ $-$100 $-$ $-$130 {\kms}. We infer that the H${}_2$ emission arises from shocked gas entrained by a high-velocity outflow. Population diagrams of H${}_2$ lines imply that the gas is thermalized at a temperature of 2,500 $-$ 3,000 K and the emission results from shock excitation.

Accepted for publication in ApJ

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