IRAS : A New Water Fountain PPN Fonda Day (UNM), Ylva Pihlstrom (UNM), Mark Claussen (NRAO), & Raghvendra Sahai (JPL/Caltech)

Water Fountain Pre-Planetary Nebulae (PPNs) In transition from asymptotic giant branch (AGB) to planetary nebula (PN) Highly red- and blue-shifted OH & H 2 O maser emission (  v>50 km s -1 ) Bipolar distribution of masers Dynamical ages: t~100 yrs Five bona fide + several candidates

Further Motivation Obtain distances using trigonometric parallax Motion of masers relative to source Peculiar motion of source within galaxy Parallax Thesis project

IRAS OH & H 2 O emission first detected by Likkel (1989),  v>70 km s -1 Classifications: –PN –Young stellar object (YSO) –PPN

MSX Quads Sevenster (2002) Suarez, Gomez, & Miranda (2008)

VLBA Observations H 2 O 22 GHz 2 epochs: March 2004, May 2006 t on-source =3.5 hr  =20-40 mJy/channel; detections >10  Measured positions relative to reference maser

Properties of Known Water Fountain PPNs SourceI16342W43AI19134OH12.8I16552I19190 Water Maser Linear Extent (A.U.) Velocity Extent (km s -1 ) D Outflow Velocity (km s -1 ) Dynamical Age (yr) Optical Lobes Detected YesNoYesNo Outflow Collimation (deg) (?)10-13 Reference 1,23,45678 (1) Claussen, Sahai & Morris (2009) (2) Sahai et al. (1999) (3) Imai et al. (2002) (4) Diamond et al. (1985) (5) Imai, Sahai & Morris (2007) (6) Boboltz & Marvel (2007) (7) Suarez, Gomez, & Miranda (2008) (8) Day et al., submitted Comparison With Other Water Fountain PPNs

“Central” Maser Features Episodic or precessing jet?

Conclusions IRAS a true water fountain PPN –Evolved object –High velocity separation of maser emission –Bipolar, collimated jet-like outflows Characteristics typical of other known water fountain nebulae

Future Work Use multi-epoch VLBA observations to obtain distance Distance measurement will give –Progenitor mass –Mass-loss rate –Luminosity