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HIGH VELOCITY JETS IN WATER-FOUNTAIN PRE-PLANETARY NEBULAE

HIGH VELOCITY JETS IN WATER-FOUNTAIN PRE-PLANETARY NEBULAE. Mark Claussen, NRAO July 30, 2003 APN III, Mt. Rainier, WA. Talk Outline. Water Fountain Pre-Planetary Nebulae W43 A (Imai et al.) IRAS 16342-3814 (Claussen et al.) More Water Fountains ? Summary.

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HIGH VELOCITY JETS IN WATER-FOUNTAIN PRE-PLANETARY NEBULAE

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  1. HIGH VELOCITY JETS IN WATER-FOUNTAIN PRE-PLANETARY NEBULAE Mark Claussen, NRAO July 30, 2003 APN III, Mt. Rainier, WA

  2. Talk Outline • Water Fountain Pre-Planetary Nebulae • W43 A (Imai et al.) • IRAS 16342-3814 (Claussen et al.) • More Water Fountains ? • Summary Collaborators: Raghvendra Sahai and Mark Morris July 30, 2003 APN III

  3. Water fountains: sites of on-going jet formation W43A High velocity H2O masers (Likkel et al. 1992) • V(H2O) >= 100 km/s • Clear double peaks • Symmetric with respect to the systemic velocity IRAS 19134+2131 IRAS 16342-3814

  4. Water fountains: sites of on-going jet formation W43A High velocity H2O masers (Likkel et al. 1992) • Newly-formed jets or extreme super winds ? • How old ? • How to produce ? • Young stellar objects ? IRAS 19134+2131 IRAS 16342-3814

  5. W43 A H2O maser kinematics in 2002 Imai & Diamond (2003)

  6. The W43A jet is precessing ! Period ~ 55 years Amplitude ~ 5 degrees Inclination ~ 39 degrees A consistent model at each epoch Direct estimate of the distance: ~2.6 kpc, origin location, and jet ignition time (~30 yr ago)

  7. IRAS 16342 –3814 Sahai et al. 1999

  8. Water Masers Mapped with the VLA --- Morris et al. 2003 -68 km/s 155 km/s IRAS 16342 –3814 Sahai et al. 1999

  9. IRAS 16342-3814, VLBA February 2003

  10. IRAS 16342-3814, VLBA February 2003 Length of this line is ~2975 mas, p.a. is 66 degrees (E of N) Line drawn between strongest red and blue shifted features. We measure the angular length of this line to better than one mas. 2000 AU

  11. 200 AU

  12. Red-shifted masers, VLBA February 2002 Line connecting strongest red and blue shifted maser features. 200 AU

  13. 10 AU

  14. Blue-shifted masers, VLBA February 2002 10 AU Line connecting strongest red and blue shifted maser features.

  15. IRAS16342-3814 Blue-Shifted Water Masers February 2002 March 2002 April 2002 May 2002 10 AU

  16. IRAS 16342-3814 VLBA Observations • First four epochs each separated by ~1 month in 2002 • Date Separation Position Angle • 03 February 2972.0 mas 66.0 deg • 03 March 2973.6 66.1 • 04 April 2975.0 66.1 • 05 May 2979.6 66.1 July 30, 2003 APN III

  17. Results of IRAS 16342-3814 VLBA Observations • For first four epochs, separation expands at an • an average rate of 287 km/s. (143 km/s in each • direction if divided equally, assumes a distance of • 2 kpc; Sahai et al. 1999) 3-D velocities +/- 185 km/s. • The small scale structure is reminiscent of bow • shocks seen in water maser proper motion studies • of YSO’s. • Over 3000 AU length, the masers get spread out • a maximum of 150 AU, collimation of ~ 3 deg. July 30, 2003 APN III

  18. Results of IRAS 16342-3814 VLBA Observations • Dynamical time scale is 150 years • IRAS16342 jet shows no evidence of precession • (curves and wiggles in the maser distribution in • a single epoch) as does W43 A. July 30, 2003 APN III

  19. Water Fountain Pre-Planetary Nebulae • Three examples from Likkel et al. 2 out of 3 show • similar sizes and very short dynamical scales; third • is presently being observed by Imai, Morris & Sahai. • The observations of collimated jets in these transition • sources suggest that PN morphology is shaped during • pre-PN stage. • Short dynamical times imply a very brief phase early • on the post-AGB evolution, and so water fountain PPN • are an important class of sources for understanding • the onset of axisymmetry. • Though water fountains are inherently rare, we would • like to find more of them; instituted survey of • candidates with the GBT. July 30, 2003 APN III

  20. From the GBT Survey, April 2003 Claussen & Sahai 2003

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