CO J=3-2 Emission from the "Water Fountain" Sources IRAS 16342-3814 and IRAS 18286-0959

TL;DR

This study detects and analyzes CO J=3-2 emission from two water fountain sources, revealing details about their outflows and mass loss rates, and distinguishes between different origins of the emission.

Contribution

First detection of CO J=3-2 emission from IRAS 16342-3814 and IRAS 18286-0959, with detailed morpho-kinematic modeling of their outflows.

Findings

IRAS 16342-3814 has a broad Gaussian CO profile with a 158 km/s width.

IRAS 18286-0959 shows narrow CO emission with a 3 km/s width.

The mass loss rate of IRAS 16342-3814 is estimated at ~2.9x10^-5 M_sun/yr.

Abstract

We observed CO J=3-2 emission from the "water fountain" sources, which exhibit high-velocity collimated stellar jets traced by water maser emission, with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. We detected the CO emission from two sources, IRAS 16342-3814 and IRAS 18286-0959. The IRAS 16342-3814 CO emission exhibits a spectrum that is well fit to a Gaussian profile, rather than to a parabolic profile, with a velocity width (FWHM) of 158+/-6 km/s and an intensity peak at VLSR = 50+/-2 km/s. The mass loss rate of the star is estimated to be ~2.9x10^-5 M_sun/yr. Our morpho-kinematic models suggest that the CO emission is optically thin and associated with a bipolar outflow rather than with a (cold and relatively small) torus. The IRAS 18286-0959 CO emission has a velocity width (FWHM) of 3.0+/-0.2 km/s, smaller than typically seen in AGB envelopes. The narrow velocity width of the CO emission suggests that it originates from either an interstellar molecular cloud or a slowly-rotating circumstellar envelope that harbors the water maser source.