1 / 16

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 !

flavio
Download Presentation

Summary notes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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

More Related