Rapidly evolving episodic outflow in IRAS 18113-2503: Clues to the ejection mechanism of the fastest water fountain
Por:
Orosz G., Gómez J.F., Imai H., Tafoya D., Torrelles J.M., Burns R.A., Frau P., Guerrero M.A., Miranda L.F., Perez-Torres M.A., Ramos-Larios G., Rizzo J.R., Suárez O., Uscanga L.
Publicada:
1 ene 2019
Resumen:
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. Themasers 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. © 2018 The Author(s).
Filiaciones:
Orosz G.:
Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi, XINJIANG, 830011, China
Konkoly Observatory, MTA Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklósút 15-17, Budapest, 1121, Hungary
Gómez J.F.:
Instituto de Astrofísica de Andaluciá, CSIC, Glorieta de la Astronomiá s/n, Granada, E-18008, Spain
Imai H.:
Center for General Education, Institute for Comprehensive Education, Kagoshima University, 1-21-30 Korimoto, Kagoshima, 890-0065, Japan
Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, 890-0065, Japan
Tafoya D.:
Chile Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Science, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
Torrelles J.M.:
Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, 890-0065, Japan
Institut de Ciencies de l'Espai (ICE CSIC), Can Magrans s/n, Cerdanyola del Valles, Catalonia, E-08193, Spain
Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Catalonia, E-08034, Spain
Burns R.A.:
Joint Institute for VLBI ERIC (JIVE), Oude Hoogeveensedijk 4, Dwingeloo, 7991 PD, Netherlands
Frau P.:
Private Researcher, Denmark
Guerrero M.A.:
Instituto de Astrofísica de Andaluciá, CSIC, Glorieta de la Astronomiá s/n, Granada, E-18008, Spain
Miranda L.F.:
Instituto de Astrofísica de Andaluciá, CSIC, Glorieta de la Astronomiá s/n, Granada, E-18008, Spain
Perez-Torres M.A.:
Instituto de Astrofísica de Andaluciá, CSIC, Glorieta de la Astronomiá s/n, Granada, E-18008, Spain
Ramos-Larios G.:
Instituto de Astronomía y Meteorología, CUCEI, Universidad de Guadalajara, Av. Vallarta No. 2602, Col. Arcos Vallarta, Guadalajara, Jalisco, 44130, Mexico
Rizzo J.R.:
Centro de Astrobiología (INTA-CSIC), Ctra. M-108, km. 4, Torrejón de Ardoz, Madrid, E-28850, Spain
Suárez O.:
Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Bd de l'Observatoire, CS 34229, Nice cedex 4, F-06304, France
Uscanga L.:
Departamento de Astronomía, Universidad de Guanajuato, A.P. 144, Guanajuato, Gto., 36000, Mexico
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