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Stellar molecular jets trace by maser emission

Hiroshi Imai (Kagoshima University)

IAU Symposium 242: 14 March 2007, Alice Springs, Australia

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Stellar molecular jets trace by maser emission

Hiroshi Imai (Kagoshima University)Combination of collaborations with Philip Diamond, Wouter Vlemmings (Jodrell Bank Obs., UK) Mark Morris (UCLA, USA) Raghvendra Sahai (JPL/NASA, USA) Shuji Deguchi (Nobeyama Radio Obs., Japan) Jun-ichi Nakashima (ASIAA, Taiwan) Sun Kwok (Univ. Hong Kong, China) Kumiko Obara, Toshihiro Omodaka (Kagoshima Univ.,

Japan) Tetsuo Sasao (NAOJ, Japan)

IAU Symposium 242: 14 March 2007, Alice Springs, Australia

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Transition from spherically symmetric

to asymmetric mass loss flow

When/how is a bipolar jet launched in the final stellar evolution?

Egg Nebula NASAⓒ

Betelgeuse NASAⓒ

Hen2-90 (Sahai et al. 1998)

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“Water fountains” in AGB/post-AGB phases Molecular rather than

optical emission jets Expansion velocity Vexp (H2O)

>> Vexp (OH1612MHz) (~30 km/s)

Evolved starsdifficulty in evolved star identificationc.f identification with SPITZER/AKARI

1612 MHz OH maser withperiodic flux variation

Detection of SiO masers

W43A

IRAS16342-3814

IRAS19134+2131

High velocity stellar H2O maser sources(Likkel et al. 1992)

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10 water fountains identified to date

W43A (Diamond et al. 1985; Imai et al. 2002, 2005; Vlemmings et al.

2006)IRAS 19134+2131 (Imai et al. 2004; 2007 in prep.) IRAS 16342-3814 (Sahai et al. 1999; Morris et al. 2003; Claussen et al. 2004)OH 12.8-0.9 (Boboltz & Marvel 2005)IRAS18286-0959 (Deguchi et al. 2007; Imai et al. in

prep.) IRAS18460-0151 (Deguchi et al. 2007; Imai et al. in

prep.) IRAS18596+0315 (Deacon et al. 2007) IRAS15445-5449 (Deacon et al. 2007) IRAS15544-5332 (Deacon et al. 2007) IRAS18043-2116 (Deacon et al. 2007)

Chapman’stalk

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Recent topics of water fountains

MHD jets! (Vlemmings’ talk)Lifetime and timing

Equatorial flow?Ballistic corkscrew jets?

Location and motion in the GalaxyPrecursors of water fountain

(e.g. WX Psc, IRC-10414)

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Lifetime and timing

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Dynamical age estimation

H2O maser proper motions in W43A (Imai et al. 2002; Imai et al. 2005; Imai & Diamond in Prep.)

Jet velocity =145 km/s, dynamical age ~50 yr

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Dynamical ages (now)

IRAS16342-3814: ~100 yr (Morris et al. 2004) OH12.8-0.9: ~70 yr (Boboltz & Marvel 2005)IRAS18286-0959: ~15 yr (Imai et al. in prep.)W43A: ~50 yr (Imai & Diamond in prep.)IRAS18460-0151: ~5 yr (Imai et al. in prep.)IRAS19134+2131: ~50 yr (Imai et al. in prep.)

-23 - -10 km s-1 -121- -117 km s-1

IRAS 19134+2131

(Imai et al. in prep.)

~Human lifetime

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1612 MHz OH masers

Imai et al. (2002)

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1612 MHz OH masers

OH maser shell (R~500 AU, Vexp=9km/s) Periodic OH maser variation (P~360d, Herman & Habing 1985)

1612 MHz OH masers (Imai & Diamond in prep.)

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How visible is W43A?

SiO masers (Nakashima & Deguchi 2002; Imai et al. 2005) Dust envelope in 2.7 mm emission: R< 3000 AU Envelope dynamical age T~ 260 years (OH), 1600 years

(dust)

SPITZER/GLIMPSE Image (Deguchi et al. 2007)

20000 AU at 2.6 kpc

+H2O & OH masers

2.7 mm continuum Image (Imai et al.)

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Transition to pre-planetary nebula (PPN)

phaseIRAS 19134+2131(by R. Sahai)

Visible in visual lightVisible in mid-IR

c.f. IRAS 16342-3814 (Sahai et al. 2001)

W43A(Deguchi et al. 2007)

c.f. OH12.8-0.9, IRAS18286-0959, IRAS18460-0151

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Quenching water fountainwithin < 1000 years

Gomez’s talk

Photodissociation destroying H2O molecules

Tip of jet achieves to the outer low-density region of a circumstellar envelope

5000 AU

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Equatorial flowsW43A

IRAS 18286-0959IRAS 18460-0151

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Wide opening angle biconical SiO maser flow

(~15 km/s)|

within 10 AU|

H2O maser jet

(Imai et al. 2005)(Imai et al. in prep.)

Where is a disk?

SiO/H2O maser locations

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Proper motion in the equatorial flow

W43A(Imai & Diamond in prep)

Flow velocity ~30 km/s

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IRAS 18460-0151(Deguchi et al. 2007)

Fastest (~350 km s-1) and youngest (t~5 yr) water fountain!

Equatorial flow (Vexp~30 km s-1)?

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IRAS 18286-0959(Deguchi et al. 2007)

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Ballistic corkscrew jets

IRAS 16342-3814W43A

IRAS 19134+2131

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W43A in detail: Jet precession

Precession period ~55 yearsPrecession angle amplitude ~5°

Imai et al. 2005

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Corkscrew jet?Bow shock front?

W43A (Imai & Diamond in prep)

Proper motions with a systemic velocity vector subtracted

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Corkscrew jet?Bow shock

front?

(VLA)

500 AU at 8 kpc

(VLBA)

(VLBA)

Imai et al. (2004) Imai et al. (2007) IRAS19134+2131

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Corkscrew jet!IRAS16342-3814 (Sahai et al. 2005)

Lp image with Keck

What happens in the H2O maserproper motions?

Lp (red), Kp (green), HST (blue) image

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Location and motion in

the Milky Way GalaxyIRAS19134+2131

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Maser motion with respect toa position-reference QSO- Exploring the roots of water

fountain -

Galacticrotation

H2O masers in IRAS 19134+2131 (Imai et al. 2007)

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Annual parallax and

Galactic rotation

Location and motion

in the Galaxy

Annual parallax distance = 8.0+0.9-0.7 kpc

Location: (R, θ, z)=(7.4+0.4-0.3 kpc, 62±5 deg, 650+70

-60 pc) 3D velocity (VR, Vθ, Vz) =(3+53

-46, 125+20-28, 8+48

-39 )[km/s]

ⒸKagaya

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Location and velocity in the Galaxy

Progenitors of bipolar PNe may be higher mass stars located near the Galactic plane (Manchado 2004).

Single intermediate-mass evolved star can create both a collimated jet and an equatorial flow

(not accretion disk). (Blackman et al. 2001; S. Miyaji in private communication)

Travel time from the Galactic plane 1.1-7.7 x 107 years M*< 5-5.8 M◉

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SummaryMagneto-hydrodynamicalCorkscrew/precessing jetV> 100 km s-1, T~100 years

Equatorial flow V~ 30 km s-1

Evolving from AGB envelope?

M*< 5 Msun single AGB/post-AGB star(or binary <10 AU?)

Only 10 water fountainsin the whole Galaxy?

ⒸNSF