Orosz, Gábor and Gómez, J. F. and Imai, H. and Tafoya, D. and Torrelles, J. M. (2019) Rapidly evolving episodic outflow in IRAS 18113-2503: clues to the ejection mechanism of the fastest water fountain. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS, 482 (1). L40-L45. ISSN 1745-3925
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Abstract
Water fountains are evolved stars showing early stages of collimated mass-loss during transition from the asymptotic giant branch, providing valuable insight into the formation of asymmetric planetary nebulae. We report the results of multi-epoch VLBI observations, which determine the spatial and three-dimensional kinematic structure of H2O masers associated with the water fountain IRAS 18113-2503. The masers trace three pairs of high-velocity (̃150-300 km s-1) bipolar bow shocks on a scale of 0{^''.}18 (̃2000 au). The expansion velocities of the bow shocks exhibit an exponential decrease as a function of distance from the central star, which can be explained by an episodic, jet-driven outflow decelerating due to drag forces in a circumstellar envelope. Using our model, we estimate an initial ejection velocity ̃840 km s-1, a period for the ejections ̃10 yr, with the youngest being ̃12 yr old, and an average envelope density within the H2O maser region n_{H_2}{≈ }106 cm-3. We hypothesize that IRAS 18113-2503 hosts a binary central star with a separation of ̃10 au, revealing novel clues about the launching mechanisms of high-velocity collimated outflows in water fountains.
Item Type: | Article |
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Uncontrolled Keywords: | astrometry; Astrophysics - Solar and Stellar Astrophysics; stars: AGB and post-AGB; MASERS; Binaries: General; Astrophysics - Astrophysics of Galaxies; stars: jets; stars: individual (IRAS 18113-2503); |
Subjects: | Q Science / természettudomány > QB Astronomy, Astrophysics / csillagászat, asztrofizika |
SWORD Depositor: | MTMT SWORD |
Depositing User: | MTMT SWORD |
Date Deposited: | 13 Feb 2023 11:50 |
Last Modified: | 13 Feb 2023 11:50 |
URI: | http://real.mtak.hu/id/eprint/158903 |
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