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

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

3. High velocity H 2 O masers (Likkel et al. 1992) Water fountains: sites of on-going jet formation V(H 2 O) >= 100 km/s Clear double peaks Symmetric with respect to the systemic velocity W43A IRAS 16342-3814 IRAS 19134+2131

4. Water fountains: sites of on-going jet formation Newly-formed jets or extreme super winds ? How old ? How to produce ? Young stellar objects ? W43A IRAS 16342-3814 IRAS 19134+2131 High velocity H 2 O masers (Likkel et al. 1992)

5. H 2 O maser kinematics in 2002 Imai & Diamond (2003) W43 A

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

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

10. IRAS 16342-3814, VLBA February 2003

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

12. 200 AU

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

14. 10 AU

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

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

17. 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

18. 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

19. 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

20. 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

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