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A Birth and Growth of a Collimated Molecular Jet from an AGB Star

Future Directions in High Resolution Astronomy: A Celebration of the 10th Anniversary of the VLBA. A Birth and Growth of a Collimated Molecular Jet from an AGB Star. Hiroshi Imai (Joint Institute for VLBI in Europe, NL) Philip J. Diamond (Jodrell Bank Observatory, UK).

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A Birth and Growth of a Collimated Molecular Jet from an AGB Star

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  1. Future Directions in High Resolution Astronomy: A Celebration of the 10th Anniversary of the VLBA A Birth and Growth of a Collimated Molecular Jet from an AGB Star Hiroshi Imai (Joint Institute for VLBI in Europe, NL) Philip J. Diamond (Jodrell Bank Observatory, UK) • Water fountains: cites of stellar jet’s birth • W43A: an AGB star having a jet and an envelope • Implication of the W43A jet The Great Barrier Dam, the Netherlands

  2. Jet formation in final stellar evolution • Central objects of planetary nebulae (PNe) = post-AGB stars • Bipolar jets (>100 km/s, >> 1000K, ionized) • Producing complicated PN morphology Jet from a planetary nebula: Henize 2-90 (Sahai & Nyman 2000)

  3. Jet formation in final stellar evolution When such stellar jets are launched ? How to launch such stellar jets ? Jet from a planetary nebula: Henize 2-90 (Sahai & Nyman 2000)

  4. High velocity stellar molecular flows Jet Outflow • Before finding optical jet • Dragged by a (unseen) collimated jet Outflow in OH 231.8+4.2 (Alcolea et al. 2001)

  5. High velocity stellar molecular flows What is the central star? White dwarf ? Mira star ? or young star ? Outflow in OH 231.8+4.2 (Alcolea et al. 2001)

  6. Transition from AGB to post-AGB • A Mira variable (AGB star): • Pulsation • Spherical envelope • Small bipolarity • Slow wind (~10 km/s) Spherical circumstellar envelope: around RT Virginis (Imai et al. 2003, see poster no .62

  7. Transition from AGB to post-AGB A Mira-star envelope is transformed to a collimated jet smoothly ? Spherical circumstellar envelope: around RT Virginis (Imai et al. 2003, see poster no .62

  8. Water fountains: cites of on-going jet formation W43A • V(H2O) >= 100 km/s >> V(OH) =< 30 km/s • Clear double peaks • Symmetric with respect to the systemic velocity IRAS 19134+2131 IRAS 16342-3814 High velocity H2O maser sources (Likkel et al. 1992)

  9. Water fountains: cites of on-going jet formation W43A • Newly-formed jets or extreme super winds ? • How old ? • How to produce ? • Young stellar objects ? IRAS 19134+2131 IRAS 16342-3814 High velocity H2O maser sources (Likkel et al. 1992)

  10. VLBA observations of the W43A H2O/OH masers • H2O masers: Jun. 1994, Oct. 1994, Mar. 1995, Apr. 2002, Jul. 2002, Nov. 2002, Apr. 2003, ..... (now going on) Synthesized beam: ~0.5 mas Velocity resolution: 0.2 km/s • OH masers (1612, 1665 & 1667MHz): Jun. 1994, Oct. 1994, Mar. 1995, Dec. 2001, Aug. 2002, ..... (now going on) Synthesized beam: ~9 mas Velocity resolution: 0.45 km/s

  11. History of the W43A jet Birth of the molecular jet (at my birthday?) Destruction of the molecular jet (at the end of my life?) Discovery of the high-velocity masers (Genzel & Downes 1977) Discovery of the molecular jet (Imai et al. 2002) VLBA operation (Since 1993) OH maser observations (5 epochs) H2O maser observations (7 epochs) 1970 1980 1990 2000 2010 2020 2030....

  12. Highly-collimated jet of molecular gas The first one year: Imai, Obara, Diamond, Omodaka, & Sasao 2002

  13. Jet parameters (1994 - 1995) Imai et al. (2002) 21 proper motions • 3D jet speed: 145 +/-20 km/s in major axis • Standard deviation ratio: V(jet)/V(internal) = 9.5 +/-4.1 (variance-covariance analysis)

  14. Jet parameters (1994 - 1995) Imai et al. (2002) 21 proper motions • Jet alignment: length = 1700 AU, P.A.= 69.3±0.3 deg. • Cluster alignment: length = 250, 350 AU, width < 30 AU P.A.= 54.6+/-6.0 deg., 57.2+/-0.3 deg. (red, blue clusters)

  15. H2O maser kinematics in 2002 Imai & Diamond (2003)

  16. Growth of the molecular jet • Growth rate of jet ~ 300AU/ 8 years ~ 180 km/s • Birth of the jet around the year 1970

  17. A precessing jet model Point symmetry Constant-velocity motion of each maser cloud Interaction with the ambient envelope

  18. A precessing jet model Straight alignments with axis offsets >>> lifetime of maser clouds ~ 10 years

  19. The W43A jet is precessing ! Period ~ 55 years Amplitude ~ 5 degrees Inclination ~ 39 degrees

  20. The precession is true ! A consistent model at every epoch >>> direct estimation: d (~2.6 kpc), origin location, and jet ignition time (~30 yr ago)

  21. What star is W43A ? An AGB star!

  22. Periodic flux variation (P~ 400 d) in OH 1612 MHz masers (Harman & Habing 1985; van Langevelde et al. 1990) Signatures of an pulsating star Dwingeloo 25-m telescope

  23. Spherically-expanding envelope • The same systemic velocity of the H2O and OH masers (VLSR ~ 34 km/s) • Similar to Mira OH maser sources OH masers 1612 MHz OH masers

  24. Spherically-expanding envelope • The same systemic velocity of the H2O and OH masers (VLSR ~ 34 km/s) • Dynamical time scale of the envelope ~ 260 years OH masers Distance - velocity diagram

  25. When is a stellar jet launched? H2O masers and a jet in PPN (Miranda et al. 2001) • Mira stars: • Elongation of circumstellar envelop (Elitzur et al. 2003) • by jets ? or by others? • OH/IR stars: • Super winds (~1000 years) • H2O maser jets: < 100 years • Later outflows, optical jets • H2O maser segments in PPNs

  26. Morphology of planetary nebulae Determined by the envelope morphology at AGB phase, created by a stellar jet !

  27. Water fountains = Molecular jets W43A Imai, & Diamond 2003 IRAS 19134+2131 IRAS 16342-3814 UH88+Sirius image (Deguchi & Nakashima 2002)

  28. Water fountains = Molecular jets W43A IRAS 19134+2131 Morris, Sahai & Claussen 2003 IRAS 16342-3814 HST image (Sahai et al. 1999)

  29. Water fountains = Molecular jets W43A IRAS 19134+2131 Imai, Morris & Sahai 2003 3-D jet speed: ~120 km/s Dynamical time scale ~ 90 years IRAS 16342-3814 2MASS All Sky Survey image

  30. Water fountains = Molecular jets W43A Similar sizes (2000 - 4000 AU) and dynamical time scales (< 100 years) of the molecular jets ! IRAS 19134+2131 IRAS 16342-3814

  31. Duration of molecular jetin the earliest phase of stellar jets: ~ 100 years A molecular jet in W43A was born with me and will disappear with me!

  32. A sensational chance in my life! The Prince Charles, visiting in the MERLIN upgrade celebration on 28 April 2003 at Jodrell Bank Observatory, UK

  33. Schematic cartoon of W43A

  34. Thank you ! Kasteel de Haar, the Netherlands

  35. Circumstellar envelope of W43A Well developed, but compact ...... • Size < 10000 AU • Mass ~ 15 Msun • (including • foreground cloud) • Optically thin • (spectral index~3-4) 20000 AU at 2.6 kpc + H2O & OH masers 2.7 mm dust continuum emission (NMA observation) (Imai et al. 2003)

  36. Circumstellar envelope of W43A Has not be ionized yet ..... 20000 AU at 2.6 kpc + H2O & OH masers UH88+Sirius JHK-band image (Deguchi & Nakashima 2002)

  37. Signatures of going mass loss SiO maser emission (see Nakashima & Deguchi 2003) Rotating disk ? e.g. IRC -10414 (Imai et al. 1999) NML Cyg (Boboltz & Marvel 1999) OH 231.8+4.2 (Sanchez Contreras et al. 2002)

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