Article

CO J = 3-2 emission from the "water fountain" sources IRAS 16342-3814 and IRAS 18286-0959

Publications- Astronomical Society of Japan (Impact Factor: 2.07). 11/2009; 61(6). DOI: 10.1093/pasj/61.6.1365
Source: arXiv

ABSTRACT

We observed CO $J$ $=$ 3–2 emission from “water-fountain” sources, which exhibit high-velocity collimated stellar jets traced by H$_{2}$O maser emission, with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. We detected CO emission from
two sources: IRAS 16342$-$3814 and IRAS 18286$-$0959. The IRAS 16342$-$3814 CO emission exhibits a spectrum that could be well fit to a Gaussian profile, rather than to a parabolic profile, with
a velocity width (FWHM) of 158$ \pm $6 km s$^{-1}$ and an intensity peak at $V_{\rm LSR}$ $=$ 50$ \pm $2 km s$^{-1}$. The mass-loss rate of the star is estimated to be $\sim $2.9 $\times$ 10$^{-5} M_{ \odot} $yr$^{-1}$. Our morpho-kinematic models suggest that the CO emission is optically thin, and associated with a bipolar outflow rather
than with a (cold and relatively small) torus. The IRAS 18286$-$0959 CO emission has a velocity width (FWHM) of 3.0$ \pm $0.2 kms$^{-1}$, smaller than typically seen in AGB envelopes. The narrow velocity width of the CO emission suggests that it originates from
either an interstellar molecular cloud or a slowly-rotating circumstellar envelope that harbors the H$_{2}$O maser source.

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