1. Structure of circumstellar envelope around AGB and post-AGB stars Dinh-V-Trung Sun Kwok, P.J. Chiu, M.Y. Wang, S. Muller, A. Lo, N. Hirano, M. Mariappan, J. Lim Institute of Astronomy and Astrophysics Academia Sinica

2. Introduction ● Intermediate mass stars (1 M  to 8 M  ) evolve through Asymptotic Giant Branch (AGB) and eventually become Planetary Nebulae (PN) ● Mass loss during the AGB phase: 10  7 to 10  4 M  /yr Shaping must occur either at the end of AGB phase or during the short transition stage (proto-planetary nebula PPN). Morphology of envelope AGB phase: spherically symmetric PN phase: wide variety of shapes PPN phase: Bipolar more common

3. Program to study the structure of envelopes with the Sub-millimeter Array IRC+10216 CIT 6 R Scl V Hya Pi Gru IRC+10420 VY CMa IRAS 07134+1005 NGC 7027

4. Envelope around AGB stars is commonly assumed to be spherically symmetric & homogeneous. But in reality the envelope is complicated & interesting ! 1.3 mm dust continuum emission in IRC+10216 V - band Groenewegen et al. (1997) Maurron & Huggins (1999)

5. VLA data of HC 5 N J=9  8 at 23 GHz. Synthesized beam ~ 4 arcsec. Lucas & Guelin (1999) IRC+10216

6. SMA CO J=2  1 emission from R Scl Detached shell !

7. Detached shell: V exp ~ 15 km/s Present day wind: V exp ~ 10 km/s Dynamical age ~ 1700 yr Helium flash ? CO J=2  1

8.  Gru CO J=2-1 emission Poster by Chiu et al. 2005 Disk & high velocity outflow are present in envelope of a normal AGB star.

9. Molecular emission from V Hya Poster by Hirano et al. 2005 Disk & collimated high velocity outflow are present

10. Mid-IR image (Kwok et al. 2002) BIMA CO J=1  0 image 21  m Proto-Planetary nebula IRAS 07134+105 Meixner et al. (2004)

11. IRAS 07134+1005 CO J=3-2  ~ 2 arcsec.

12. CO J=3-2 emission superposed on Mid-IR image at 18  m.

13. AGB wind Torus To observer North Schematic view of IRAS 07134+1005

14. Model parameters for IRAS 07134+1005 ● Expansion velocity of the wind : 10 km/s ● Outer spherical AGB wind with mass loss 2 10 -6 M  /yr ● Axi-symmetric torus with mass loss ~ 4 10 -5 M  /yr ● Inner radius of torus ~ 6 10 16 cm or 1500 yrs in dynamical age ● Outer radius of torus ~ 9 10 16 cm or 2000 yrs in dynamical age ● Envelope is viewed at 45 degrees from below the equator

15. CO J=3-2 observation – channel maps Model channel maps

16. Brightest planetary nebula at all wavelengths Distance ~ 900 pc Central white dwarf T * ~ 198000 K Young HII region surrounded by massive molecular envelope. Rich in molecular lines and carbon chemistry NGC 7027

17. HST optical images in H , OIII & NII. HST near IR images

18. @230 GHz Beam : 2.65’’ x 1.52’’ (77°) Total flux : ~ 3.6 Jy JCMT : 3.8  0.2 Jy (Knapp et al. 1993) @ 345 GHz Beam : 1.71’’ x 0.85’’ (73°) Total flux : ~ 1.45 Jy CONTINUUM

19. 12 CO J=2-1

20. Integrated intensity 12 CO(2-1) and 1.3 mm continuum

21. Future work Combine SMA & single dish (JCMT, CSO, HHT) data recover short spacing flux Multi-line observations & molecular excitation physical conditions Effects of high velocity outflow on circumstellar envelope radiation hydrodynamics Better understanding of the physics of circumstellar envelopes.

22. Scattered light polarizationCO J=2  1 R Scl

23. Histogram: CO J=3-2 from HHT 10m telescope Red solid line: CO J=3-2 profile predicted by model

24. CO J=3-2 & continuum