2018/09/20 by Gábor Orosz, Gabor Orosz, Jose F. Gomez +21 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Asymptotic giant branch #Bipolar outflow #Gamma-ray bursts and supernovae #Maser #Meteorology #Outflow #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnrasl/sly177
published as MNRAS Letters (2019), 482, L40-L45 · Accepted for publication in Monthly Notices of the Royal Astronomical Society Letters (September 17, 2018). Supplementary material is included
openalex publication_date 2018/09/20 · arxiv created 2018/10/19 · arxiv updated 2018/10/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 nH2≈ 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.