A molecular jet in the pre-planetary nebula IRAS Hiroshi Imai (Kagoshima Univ.) Mark Morris (UCLA) Raghvendra Sahai (JPL/NASA) Hiroshi Imai (Kagoshima Univ.) Mark Morris (UCLA) Raghvendra Sahai (JPL/NASA) 8th EVN Symposium on 27 Sep. 2006

From spherically symmetric to asymmetric flow FWhen/how is a bipolar jet launched in the final stellar evolution? Betelgeuse ⓒ NASA Egg Nebula ⓒ NASA

“Water fountains” in AGB/post-AGB phases FV exp (H 2 O)> V exp (OH) ~ 30 km/s FOH (Boboltz & Marvel 2005) FW43A (Imai et al. 2002, 2005; Vlemmings et al. 2006) FIRAS (Imai et al. 2004) FIRAS (Sahai et al. 1999; Morris et al. 2003) FV exp (H 2 O)> V exp (OH) ~ 30 km/s FOH (Boboltz & Marvel 2005) FW43A (Imai et al. 2002, 2005; Vlemmings et al. 2006) FIRAS (Imai et al. 2004) FIRAS (Sahai et al. 1999; Morris et al. 2003) W43A IRAS IRAS Water fountains (Likkel et al. 1992)

IRAS  A kinematic distance was estimated to be ~16 kpc.  T~190 K envelope  Bipolar nebulosity in an HST image  Preplanetary nebula (PPN) phase (since Sahai et al. 2005)  No SiO, OH maser emission  F(H 2 O) < 3Jy  Long-term integration/ high precision astrometry in phase-referencing technique  A kinematic distance was estimated to be ~16 kpc.  T~190 K envelope  Bipolar nebulosity in an HST image  Preplanetary nebula (PPN) phase (since Sahai et al. 2005)  No SiO, OH maser emission  F(H 2 O) < 3Jy  Long-term integration/ high precision astrometry in phase-referencing technique 2MASS image

Maser spatio-kinematics (VLA) 500 AU at 8 kpc

Maser relative proper motions FDynamical age ~ 40 years FDuration of a water fountain ： < 100 years FTransition from AGB (W43A) to pre-planetary nebula (IRAS ) FDynamical age ~ 40 years FDuration of a water fountain ： < 100 years FTransition from AGB (W43A) to pre-planetary nebula (IRAS )

High precision maser astrometry Galactic rotation J : 2.5 deg away, ~1.9 Jy J : 2.5 deg away, ~1.9 Jy

Galactic rotation and annual parallax ! Mean motion of 3 maser features Mean motion of 3 maser features

Annual parallax distance: 8.0 kpc

Location and kinematics in the Galaxy  Location in the Galaxy (R sun ≡ 8.0 kpc Θ sun ≡ 218 km/s)  Velocity in the Galaxy  A member of the “thick component” in the Galaxy.  If kicked from the Galactic plane in the star formation process: t ~5x10 7 years (> 1.3x10 7 years for V z <50 km/s)  Bipolar PNe and OH/IR stars tend to be members of the “thin component” in the Galaxy.  Location in the Galaxy (R sun ≡ 8.0 kpc Θ sun ≡ 218 km/s)  Velocity in the Galaxy  A member of the “thick component” in the Galaxy.  If kicked from the Galactic plane in the star formation process: t ~5x10 7 years (> 1.3x10 7 years for V z <50 km/s)  Bipolar PNe and OH/IR stars tend to be members of the “thin component” in the Galaxy.

Summary FDuration of the water fountains:<100 yr FDuring the water fountain activity, transition from AGB to post-AGB phase may occur. FLikely jets in PNe have already been formed in the water fountains. FMy prediction: quenching of a water fountain before my own retirement/death. FDirect measurement of galactic rotations and distances FD~8kpc: consistent between annual parallax and advanced kinematic distances FV θ ~120 km/s, z=650 pc: member of the thick component. FDuration of the water fountains:<100 yr FDuring the water fountain activity, transition from AGB to post-AGB phase may occur. FLikely jets in PNe have already been formed in the water fountains. FMy prediction: quenching of a water fountain before my own retirement/death. FDirect measurement of galactic rotations and distances FD~8kpc: consistent between annual parallax and advanced kinematic distances FV θ ~120 km/s, z=650 pc: member of the thick component.