Download Imai et al. 2005

Stellar molecular jets trace by
maser emission
Hiroshi Imai (Kagoshima University)
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IAU Symposium 242: 14 March 2007, Alice Springs, Australia
Stellar molecular jets trace by
maser emission
Hiroshi Imai (Kagoshima University)
Combination of collaborations with
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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)
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IAU Symposium 242: 14 March 2007, Alice Springs, Australia
Betelgeuse ⓒ NASA
Transition from
spherically symmetric
to asymmetric
mass loss flow
Egg Nebula ⓒ NASA
Hen2-90 (Sahai et al. 1998)
When/how is a bipolar
jet launched in the
final stellar evolution?
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W43A
“Water fountains” in
AGB/post-AGB phases
 Molecular rather than
optical emission jets
 Expansion velocity Vexp
IRAS
19134+2131
(H2O) >> Vexp (OH1612MHz)
(~30 km/s)
 Evolved stars
difficulty in evolved star identification
c.f identification with SPITZER/AKARI
IRAS
16342-3814
 1612 MHz OH maser with
periodic flux variation
 Detection of SiO masers
High velocity stellar H2O maser sources
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(Likkel et al. 1992)
10 water fountains identified to date
W43A
(Diamond et al. 1985; Imai et al. 2002, 2005; Vlemmings et al. 2006)
IRAS 19134+2131
IRAS 16342-3814
(Imai et al. 2004; 2007 in prep.)
(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’s
talk
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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 Galaxy
Precursors 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 8
Dynamical ages (now)
-23 - -10 km s-1
-121- -117 km s-1
~Human lifetime
IRAS 19134+2131
(Imai et al. in prep.)
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.)
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1612 MHz OH masers
Imai et al. (2002)
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1612 MHz OH masers
1612 MHz OH masers (Imai & Diamond in prep.)
 OH maser shell (R~500 AU, Vexp=9km/s)
 Periodic OH maser variation (P~360d, Herman & Habing 1985)
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How visible is W43A?
SPITZER/GLIMPSE
Image
(Deguchi et al. 2007)
2.7 mm continuum
Image (Imai et al.)
+
H2O & OH
masers
20000 AU at 2.6 kpc
 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)
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Transition to
pre-planetary nebula (PPN) phase
Visible in mid-IR
W43A
(Deguchi et al. 2007)
c.f. OH12.8-0.9,
IRAS18286-0959, IRAS18460-0151
Visible in visual light
IRAS 19134+2131
(by R. Sahai)
c.f. IRAS 16342-3814
(Sahai et al. 2001)
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Quenching water fountain
within < 1000 years
Photodissociation
destroying
H2O molecules
5000 AU
Tip of jet achieves to
the outer low-density
region of
a circumstellar envelope
Gomez’s talk
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Equatorial flows
W43A
IRAS 18286-0959
IRAS 18460-0151
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SiO/H2O maser locations
Wide opening
angle biconical
SiO maser flow
(~15 km/s)
|
within 10 AU
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H2O maser jet
(Imai et al. 2005)
(Imai et al. in prep.)
Where is a disk?
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Proper motion in the equatorial flow
 Flow velocity ~30 km/s
W43A
(Imai & Diamond in prep)
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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 16342-3814
W43A
IRAS 19134+2131
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W43A in detail: Jet precession
Imai et al. 2005
Precession period ~55 years
Precession angle amplitude ~5°
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Corkscrew jet?
Bow shock front?
Proper motions with
a systemic velocity vector subtracted
W43A (Imai & Diamond in prep)
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(VLA)
Corkscrew jet?
Bow shock front?
(VLBA)
(VLBA)
500 AU at 8 kpc
Imai et al. (2004)
IRAS19134+2131
Imai et al. (2007)
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Corkscrew jet!
IRAS16342-3814
(Sahai et al. 2005)
Lp image with Keck
What happens
in the H2O maser
proper motions?
Lp (red), Kp (green),
HST (blue) image 24
Location and motion in
the Milky Way Galaxy
IRAS19134+2131
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Maser motion with respect to
a position-reference QSO
- Exploring the roots of water fountain -
Galactic
rotation
H2O masers in IRAS 19134+2131 (Imai et al. 2007)
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Annual parallax and
Galactic rotation
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ⒸKagaya
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]
Location and velocity in the Galaxy
Travel time from
the Galactic plane
 1.1-7.7 x 107 years
 M*< 5-5.8 M◉
 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)
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Summary
Magneto-hydrodynamical
Corkscrew/precessing jet
V> 100 km s-1, T~100 years
M*< 5 Msun single
AGB/post-AGB star
(or binary <10 AU?)
Equatorial flow
V~ 30 km s-1
Evolving from
AGB envelope?
Only 10 water fountains
in the whole Galaxy?
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ⒸNSF