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Panoramic Views of Water Fountain Sources Panoramic Views of Water Fountain Sources

Panoramic Views of Water Fountain Sources - PowerPoint Presentation

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Panoramic Views of Water Fountain Sources - PPT Presentation

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 ID: 289288

h2o maser iras agb maser h2o agb iras imai jet water w43a envelope masers velocity 2005 2007 equatorial flow

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Slide1

Panoramic Views of Water Fountain Sources

Hiroshi ImaiGraduate School of Science and EngineeringKagoshima University

A Neapolitan of Masers: Variability, Magnetism and VLBI

20

May 2013,

CSIRO CASS,

AustraliaSlide2

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. 2007

H

2

O maser

spectrum

(

Likkel

et al. 1992)Slide3

Masers in water fountains

Dynamical centers

within 70 AU

Systemic velocities

w

ithin 3 km/s

H

2O and OH

masers(Imai et al. 2002)SiO and H2O masers(Imai et al. 2005)

SPITZER/GLIMPSE image around W43A (Deguchi et al. 2007)

VLT 11.85

micron image of W43A (Lagadec et al. 2011)Slide4

Mechanism of stellar jet launch

See Vlemmings’s talk about magnetic fieldMechanism of planetary nebula shaping by jetCharacter of stellar system: single star v.s

. binaryDynamical time scales: t

dyn(H2O)=l

/

vexp<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 H2O maser components?

Open issues of water fountainsSlide5

Luminosities and

secular motions of the water fountain systemsAstrometry with VLBA and VERAThermal molecular emission (

12CO, 13CO)High velocity molecular component

Hot-bottom burning in nucleosynthesis Kinematics of low velocity H

2

O maser componentsRelic AGB envelope or newly developed equatorial flow?Three new aspects in this talkSlide6

SiO masers: W43A with VLA,

σ~3 mas (Imai et al. 2005)H2O masers: W43A; IRAS 19134+2131; IRAS 18286-0959; IRAS 18460-0151 with VLBA and VERA, σ

~0.2 mas (Imai et al. 2005, 2007, 2013, submitted)1612 MHz OH masers: W43A; IRAS 18286-0959; IRAS 18460-0151

with VLBA and EVN, σ~2 mas (Imai et al. 2005, 2007, 2013, submitted)

Astrometry of water fountains

Measurement of absolute coordinates and H2O maser trigonometrySlide7

Trigonometric parallax distances

Planning water fountain astrometry with VLBA, VERA(after upgrade or KVN+VERA), and LBA including W43ASlide8

Large deviation from Galactic rotation

Low galactic latitude: suggesting intermediate-mass, old population

IRAS

source

18286-095918460-015119134+2131D [kpc]3.6±0.62.1±0.6

8.0+0.9-0.7R [kpc]

4.8±0.56.3±0.57.4

+0.4-0.3z [pc]7±17±2650+70-60VR [km/s]

51±17100±143+53-46Vθ [km/s]169±22286±16

125+20-28

Vz [km/s]-2±20-9±118+48-39ReferenceImai+2013(in press)Imai+2013(submitted)

Imai+2007Slide9

source

D [kpc]

F12[Jy

](BC

)

12Lbol [Lsun]IRAS 15103-57542.310.864.246800IRAS 16342-3814

2.016.2107.213000

IRAS 18286-09593.6

24.874.8312900W 43A2.623.7315.483900IRAS 18460-01512.1—6.720.902.885490—5000IRAS 18596+0315

1.6?2.59923.28290?IRAS 19134+21318.05.0588.3135000IRAS 19190+11028.61.5904.8311000

Bolometric luminosities of water fountain sources

van der Veen & Breukers 1989Nakashima et al. 2000Really intermediate mass AGB/post-AGB stars?Slide10

H

2

O

OH

CO

J

=3→2 emission from

IRAS

16342-

3814

(Imai et al. 2012)Thermal molecular emission from water fountains

Atacama SubmillimeterTelescope Experiment(ASTE) 10 m telescope

See also 12CO and

13

CO J=2-

1

detections by

He et al. (2008)

and

Rizzo et al. (2011).Slide11

SHAPE

modelling

Spherical envelope (+ expanding torus) + collimated jet

Gas

density

ρ

(r)

Gas clump distribution and relative opacity obtained by Monte-Carlo

method simulation

Steffen et al. 2011HST image(Sahai et al. 2005)

SHAPE

model

Model geometry

V

torus

=15 km/s

V

jet

=550 kmsSlide12

Extremely low

12

C/13C 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 12CO, but high intensity ratio cannot be explained12CO/13CO i

ntensity ratio ~1.5  12C/13

C isotopic ratio~1.3Hot-bottom burning of nucleosynthesis as found in intermediate-mass AGB/post AGB starSlide13

Relic AGB envelope or new equatorial flow?

W43A (1994—2005)

L

ow velocity components (

V

LSR =9—70 km/s), Vsys (W43A)~35 km/sSlide14

IRAS 18286-0959

M

aser motions in 2006—2007

(

Imai et al. 2013)

Short-lived, low-velocity features Vexp < 30 km/s

1612

MHz

OH maserDouble helix jet model(Yung et al. 2011)

SystemicmotionSlide15

V

exp(OH)~Vexp(H2O low)~20 km/s

Dynamical centers within 20 AUΔVsys

=10-40 km/sDeveloped relic AGB envelope

IRAS 18460-0151

(Imai et al. 2013 submitted)Slide16

Ignition of equatorial flow?

V

sys~40 km/s

IRAS 16342-3814(Claussen et al. 2009)

V

exp(H2O)~ 180 km/sVexp(OH)~70 km/sSee also e.g. OH 009.8-0.4 (Walsh et al. 2009) Slide17

Coevolution of jet and equatorial torus/

flow with a time lag

High

velocity H2O masers in WFsIgnition of jet

Maser region

comparable to MIR/optical lobes Low velocity H2O masers in WFsShorter ttorus indicating association

with relic AGB envelopeTransition from relic envelope to equatorial

torus/flow?Slide18

Maser region is really evolving.

Recurrent maser excitationSome point symmetryBut different feature group spacing between blue- and red-shifted lobes

Tdyn

(maser) < Tdyn (jet) or T

dyn

(envelope) Decadal evolution of the W43A H2O masers along the jet(Chong et al. in prep.)Slide19

L

arge deviation of WF sources in the Galactic midplane from Galactic rotation Possible low 12C/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 VLBITrue tdyn of WF jet and envelope/torus measured with ALMANew WF candidates discovered by unbiased maser surveys (H2O: HOPS, OH: SPLASH & GASKAP)Summary and future perspectives