Panoramic Views of Water Fountain Sources Hiroshi Imai Graduate School of Science and Engineering Kagoshima University A Neapolitan of Masers: Variability, Magnetism and VLBI 20 May 2013, CSIRO CASS, Australia

Water fountain highly collimated, fast, stellar, molecular jet from AGB to post-AGB star, from spherical symmetric to asymmetric circumstellar envelope Egg Nebula (post-AGB star) ⓒ NASA Betelgeuse (Mira variable) ⓒ NASA W43A (OH/IR star) water fountain Deguchi et al H 2 O maser spectrum (Likkel et al. 1992)

Masers in water fountains Dynamical centers within 70 AU Systemic velocities within 3 km/s H 2 O and OH masers (Imai et al. 2002) SiO and H 2 O masers (Imai et al. 2005) SPITZER/GLIMPSE image around W43A (Deguchi et al. 2007) VLT micron image of W43A (Lagadec et al. 2011)

 Mechanism of stellar jet launch  See Vlemmings’s talk about magnetic field  Mechanism of planetary nebula shaping by jet  Character of stellar system: single star v.s. binary  Dynamical time scales: t dyn (H2O)=l/v exp <100 yr, But equal to true ages? Can we see evolution/devolution?  Precessing jets? Recurrent jet ignitions?  Main-sequence mass and evolutionary phase of host star?  What is low-velocity H 2 O maser components? Open issues of water fountains

1.Luminosities and secular motions of the water fountain systems  Astrometry with VLBA and VERA 2.Thermal molecular emission ( 12 CO, 13 CO)  High velocity molecular component  Hot-bottom burning in nucleosynthesis 3.Kinematics of low velocity H 2 O maser components  Relic AGB envelope or newly developed equatorial flow? Three new aspects in this talk

 SiO masers: W43A with VLA, σ~3 mas (Imai et al. 2005)  H 2 O masers: W43A; IRAS ; IRAS ; IRAS with VLBA and VERA, σ~0.2 mas (Imai et al. 2005, 2007, 2013, submitted)  1612 MHz OH masers: W43A; IRAS ; IRAS with VLBA and EVN, σ~2 mas (Imai et al. 2005, 2007, 2013, submitted) Astrometry of water fountains Measurement of absolute coordinates and H 2 O maser trigonometry

Trigonometric parallax distances Planning water fountain astrometry with VLBA, VERA (after upgrade or KVN+VERA), and LBA including W43A

Large deviation from Galactic rotation Low galactic latitude: suggesting intermediate-mass, old population IRAS source D [kpc]3.6±0.62.1± R [kpc]4.8±0.56.3± z [pc]7±17± V R [km/s]51±17100± V θ [km/s]169±22286± V z [km/s]-2±20-9± ReferenceImai+2013 (in press) Imai+2013 (submitted) Imai+2007

sourceD [kpc]F 12 [Jy](BC) 12 L bol [L sun ] IRAS IRAS IRAS W 43A IRAS — —5000 IRAS ? ? IRAS IRAS Bolometric luminosities of water fountain sources van der Veen & Breukers 1989 Nakashima et al Really intermediate mass AGB/post-AGB stars?

H2OH2O OH CO J=3→2 emission from IRAS (Imai et al. 2012) Thermal molecular emission from water fountains Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope See also 12 CO and 13 CO J=2-1 detections by He et al. (2008) and Rizzo et al. (2011).

SHAPE modelling Spherical envelope (+ expanding torus) + collimated jet Gas density ρ(r) Gas clump distribution and relative opacity obtained by Monte-Carlo method simulation Ste ff en et al HST image (Sahai et al. 2005) SHAPE model Model geometry V torus =15 km/s V jet =550 kms

Extremely low 12 C/ 13 C isotopic ratio 12 CO 13 CO SHAPE simulation  Estimation of possible absolute opacity with RADEX/LAMDA (van der Tak et al. 2007; Schöier et al. 2005)  optically thick 12 CO, but high intensity ratio cannot be explained  12 CO/ 13 CO intensity ratio ~1.5  12 C/ 13 C isotopic ratio~1.3 Hot-bottom burning of nucleosynthesis as found in intermediate-mass AGB/post AGB star

Relic AGB envelope or new equatorial flow? W43A (1994—2005) Low velocity components (V LSR =9—70 km/s), V sys (W43A)~35 km/s

IRAS Maser motions in 2006—2007 (Imai et al. 2013) Short-lived, low-velocity features V exp < 30 km/s 1612 MHz OH maser Double helix jet model (Yung et al. 2011) Systemic motion

 V exp (OH)~V exp (H 2 O low)~20 km/s  Dynamical centers within 20 AU  ΔV sys =10-40 km/s Developed relic AGB envelope IRAS (Imai et al submitted)

Ignition of equatorial flow? V sys ~40 km/s IRAS (Claussen et al. 2009)  V exp (H 2 O)~ 180 km/s  V exp (OH)~70 km/s See also e.g. OH (Walsh et al. 2009)

Coevolution of jet and equatorial torus/flow with a time lag  High velocity H2O masers in WFs  Ignition of jet  Maser region comparable to MIR/optical lobes  Low velocity H2O masers in WFs  Shorter t torus indicating association with relic AGB envelope  Transition from relic envelope to equatorial torus/flow?

 Maser region is really evolving.  Recurrent maser excitation  Some point symmetry  But different feature group spacing between blue- and red-shifted lobes T dyn (maser) < T dyn (jet) or T dyn (envelope) Decadal evolution of the W43A H 2 O masers along the jet (Chong et al. in prep.)

 Large deviation of WF sources in the Galactic midplane from Galactic rotation  Possible low 12 C/ 13 C intensity ratio suggesting the hot-bottom burning nucleosynthesis in an intermediate-mass AGB star  Variety of spatio-kinematics of low-velocity H2O maser components: transition from relic AGB envelope to equatorial flow or independent phenomena?  Visible decadal evolution/devolution of WF H2O masers  L* derived from maser trigonometry in forthcoming VLBI  True t dyn of WF jet and envelope/torus measured with ALMA  New WF candidates discovered by unbiased maser surveys (H2O: HOPS, OH: SPLASH & GASKAP) Summary and future perspectives