A Fast bipolar H2 outflow from IRAS 16342-3814: an old star reliving its youth

Abstract

Some evolved stars in the pre-planetary nebula phase produce highly-collimated molecular outflows that resemble the accretion-driven jets and outflows from pre-main sequence stars. We show that IRAS 16342-3814 (the Water Fountain Nebula) is such an object and present K-band integral field spectroscopy revealing a fast (> 150 km/s) bipolar H2 outflow. The H2 emission is shock excited and may arise in fast-moving clumps, accelerated by the previously observed precessing jet. The total luminosity in H2 is 0.37 L${}_{\odot }$ which is comparable with that of accretion-powered outflows from Class 0 protostars. We also detect CO overtone bandhead emission in the scattered continuum, indicating hot molecular gas close to the centre, a feature also observed in a number of protostars with active jets. It seems likely that the jet and outflow in IRAS 16342-3814 are powered by accretion onto a binary companion.

Accepted for publication in Monthly Notices of the Royal Astronomical Society

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Cited by in corpus (3)

• ALMA Observations of the Water Fountain Pre-Planetary Nebula IRAS 16342-3814: High-velocity bipolar jets and an Expanding Torus
• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• Numerical simulations of wind-driven protoplanetary nebulae. I. near-infrared emission