IRAS 18113-2503: THE WATER FOUNTAIN WITH THE FASTEST JET?
- Instituto de Astrofisica de Andalucia, CSIC, Apartado 3004, E-18080 Granada (Spain)
- Centro de Astrobiologia, CSIC-INTA, E-28850 Madrid (Spain)
- UMR 6525 H. Fizeau, Universite de Nice Sophia Antipolis, CNRS, OCA. Parc Valrose, 06108 Nice Cedex 2 (France)
- Consejo Superior de Investigaciones CientIficas, C/Serrano 117, E-28006 Madrid (Spain)
- Instituto de AstronomIa y MeteorologIa, Av. Vallarta No. 2602, Col. Arcos Vallarta, C.P. 44130 Guadalajara, Jalisco (Mexico)
We present Expanded Very Large Array water maser observations at 22 GHz toward the source IRAS 18113-2503. Maser components span over a very high velocity range of {approx_equal} 500 km s{sup -1}, the second largest found in a Galactic maser, only surpassed by the high-mass star-forming region W49N. Maser components are grouped into a blueshifted and a redshifted cluster, separated by 0.''12. Further mid-IR and radio data suggest that IRAS 18113-2503 is a post-asymptotic giant branch star, thus a new bona fide member of the rare class of 'water fountains' (WFs). It is the evolved object with the largest total velocity spread in its water masers and with the highest velocity dispersion within its redshifted and blueshifted lobes ({approx_equal} 170 km s{sup -1}). The large total velocity range of emission probably indicates that IRAS 18113-2503 has the fastest jet among the known WF stars. On the other hand, the remarkably high velocity dispersion within each lobe may be interpreted in terms of shocks produced by an episode of mass ejection whose velocity increased up to very high values or, alternatively, by projection effects in a jet with a large opening angle and/or precessing motions.
- OSTI ID:
- 21565447
- Journal Information:
- Astrophysical Journal Letters, Vol. 739, Issue 1; Other Information: DOI: 10.1088/2041-8205/739/1/L14; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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