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Summary notes

Summary notes. Harm Habing Leiden Observatory. my first APN-conference. after three weeks of conferences elsewhere, I got this! (after Julius Caesar) veni, vidi, victus : I came, I saw, I was overcome well-chosen format; beautiful science !

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Summary notes

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  1. Summary notes HarmHabing Leiden Observatory

  2. my first APN-conference • after three weeks of conferences elsewhere, I got this! • (after Julius Caesar) veni, vidi, victus: I came, I saw, I was overcome • well-chosen format; beautiful science ! • speakers: thank you for mostly excellent presentations • posters: many of high quality: compact, well-structured and with all the information this reader would like to see

  3. first, some general remarks….

  4. finding the distance • progress seriously slowed down by the lack of good distance estimates; some suggestions: • compare proper motions with radial velocities (e.g. H2O masers in Orion) • use foreground extinction + near-IR surveys (DENIS and 2MASS) • use galactic rotation (high-mass PN progenitors) • study low-mass PN progenitors in MWG bulge • study PNe in the MCs (Stanghellini+) • wait for GAIA

  5. large and accurate data bases (I) • mass production of accurate measurements lead to ¨complete¨ data bases that are publicly available • analyze the data base or use it as a starting point for additional observations • analysis helped by well-designed software on fast computers using advanced models and • by the accessebility of many more telescopes of intermediate size and excellent detectors and spectrographs

  6. large and accurate data bases (II) • It pays of to come back to projects that in the past were too demanding, but that are bow rather easy • rapid progress: several examples shown at this conference (Bujarrabal, Castro-Carrizo, Meixner) • To study variability: use the data bases of EROS, MACHO, OGLE or of more recent similar projects

  7. multi-wavelength, high resolution • detailed studies of single objects (¨the world in a nutshell….¨, Hamlet?) based on follow-up observations on telescopes of intermediate to large size and in different wavelength regimes • The latest missing wavelength regime, that of the X-rays, has now become accessible • examples: Calabash nebula (OH 231.8+4.2, Alcolea), Cat´s eye (Balick), Red Rectangle (or `blue circle´, Van Winckel), V838 (Bond)

  8. computer simulations • 3D hydrocodes are now state of the art • the addition of the third dimension IS significant (e.g. Icke) • presentation of results through movies impressive- but often rather qualitative? • MHD can no longer be avoided (e.g. Blackman, Frank and company)

  9. classification • several somewhat different classification systems based purely on a description of what one sees (phenomenology) • no convergence of the systems • is it worth the effort? should one not concentrate on physical properties (size and number of hot X-ray bubbles, jets) • reminder: classification of galaxies

  10. andnow the AGB circus..

  11. TP-AGB stars: theory (I) • small core, huge convective envelope, pulsations, extended atmosphere dominated by molecular lines and bands • mass loss ends the evolution of each star • hundreds of models available • several evolutionary sequences available (Vassiliadis & Wood; Blöcker & Schönberner; others); evolution at constant luminosity. • the gap between AGB stars, postAGb stars is becoming narrow • however, ….

  12. TP-AGB stars: theory (II) • basic and ad hoc assumptions needed: • concerning convection (recently there appear to have been breakthroughs) • concerning pulsation (and what about the four (log period versus Mbol) relations?) • concerning the atmospheres: periodic behavior, molecular opacity, dust formation • concerning mass loss rates: the discovery of ¨the cliff¨, why did it take so long?

  13. TP-AGB stars: observations (I) • thousands of galactic TP-AGB stars known: ISOGAL, MSX, DENIS, 2MASS, OH/IR surveys • individual luminosities for several samples: around galactic centre, in LMC & SMC and in other Local Group galaxies • estimates of mass-loss rate within factor of two; total range of rates: a few times 10e3 • most (all?) are variable: periods and amplitudes known for a significant number • four (4!) relations between log period and bolometric magnitude (Wood & MACHO)

  14. TP-AGB stars: observations (II) • stars are large, with and without envelope: size measurements possible; for ESO members: keep VLT-I in mind! • radio interferometry of masers: images and positions to within 5 mas: proper motions and parallax (but not for many….) • masers: Zeeman splitting; magnetic field

  15. post-AGB stars • have we detected all different kinds of post-AGB stars? • the SiO maser is very close to the star; the H2O maser is at, say, 10 stellar radii, and the OH really far out, the disappearance of a maser tells us about how far the disturbance of the maser conditions have traveled outward • some OH/IR stars with regular 1612 MHz masers are not AGB stars but post-AGB stars: they may be very young post-AGB stars

  16. thank you, Bruce and Noam

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