A shock-excited OH maser in a post-AGB envelope ?
arXiv:astro-ph/0011114 · doi:10.1086/318867
Abstract
We have observed a sample of OH 1612-MHz masing objects in all four OH ground--state transitions with the Australia Telescope Compact Array. One likely post-AGB object is found to emit in the 1612-MHz, 1665-MHz and 1720-MHz transitions. We discuss the evidence that this object may be an early post-AGB object and the possibility for such a circumstellar envelope to harbour a 1720-MHz maser. We argue that during a very brief period, just after the star has left the thermally-pulsing phase of the AGB and the wind velocity starts to increase, post-AGB objects might show \sath emission. The best objects to search for such emission would be those that are masing at 1612 MHz and 1665 MHz, but not at 1667 MHz nor in the 22-GHz H2O transition.
4 pages, 2 figures, LaTeX, accepted for publication in ApJ Letters
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- Enhanced OH in C-type shock waves in molecular clouds
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- Three Dimensional Magneto-Hydrodynamical Modeling of Planetary Nebuale ~ II: The Formation of Bipolar and Elliptical Nebulae with Point-Symmetric Structures and Collimated Outflows
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- Accurate OH Maser Positions From The SPLASH Survey III: The Final 96 Square Degrees
- Discrete Source Survey of 6 GHz OH emission from PNe & pPNe and first 6 GHz images of K 3-35
- Submillimeter H2O masers in water-fountain nebulae
- MAGMO: Polarimetry of 1720-MHz OH Masers towards Southern Star Forming Regions
- Deep into the Water Fountains: The case of IRAS 18043-2116