Issue |
A&A
Volume 420, Number 1, June II 2004
|
|
---|---|---|
Page(s) | 265 - 271 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20035664 | |
Published online | 14 May 2004 |
The kinematics of water masers in the stellar molecular outflow source, IRAS 19134+2131
1
Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo, The Netherlands e-mail: imai@jive.nl
2
Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562, USA e-mail: morris@astro.ucla.edu
3
Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA e-mail: Raghvendra.Sahai@jpl.nasa.gov
4
Departamento de Astronomía, Universitat de Valéncia, 46100 Burjassot, Spain e-mail: kazuya.hachisuka@uv.es
5
Instituto de Astrofísica de Canarias, La Laguna, Tenerife 38200, Spain e-mail: jraf@cca.iac.es
Corresponding author: H. Imai, hiroimai@sci.kagoshima-u.ac.jp
Received:
12
November
2003
Accepted:
4
March
2004
Using the Very Large Array (VLA) and the Very Long Baseline Array (VLBA),
we have observed water maser emission in the proto-planetary nebula candidate
IRAS 19134+2131, in which the water maser spectrum has two groups of emission features
separated in radial velocity by ~100 km s-1. The blue-shifted and red-shifted
clusters of maser features are clearly separated spatially by ~150 mas,
indicative of a fast collimated flow. However, not all of the maser features are
aligned along the axis of the flow, as is seen in the similar high-velocity
water maser source, W43A. Comparing the VLA and VLBA maps of the
water maser source, we find 4 maser features that were active for 2 years.
Using only VLBA data, we identified proper motions for 8 maser features.
The full 3D outflow velocity is estimated to be ~130 km s-1, indicating that
the dynamical age of the flow is only ~50 yr. On the basis of the relative
positions with respect to the nearby extragalactic reference source, J1925+2106,
we also obtain a secular motion of IRAS 19134+2131of
mas yr-1 along the Galactic plane toward the Galactic
centre. This indicates a “far distance" (≥16 kpc) for IRAS 19134+2131
if the Galactic rotation curve remains flat at 220 km s-1.
Key words: masers / stars: AGB and post-AGB / stars: distances / stars: kinematics / stars: winds, outflows / stars: individual: IRAS 19134+2131
© ESO, 2004
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