Summary notes
Download
1 / 16

Summary notes - PowerPoint PPT Presentation


  • 92 Views
  • Uploaded on

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 !

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Summary notes' - flavio


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Summary notes

Summary notes

HarmHabing

Leiden Observatory


My first apn conference
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



Finding the distance
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


Large and accurate data bases i
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


Large and accurate data bases ii
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


Multi wavelength high resolution
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)


Computer simulations
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)


Classification
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


And now the agb circus
andnow the AGB circus..


Tp agb stars theory i
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, ….


Tp agb stars theory ii
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?


Tp agb stars observations i
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)


Tp agb stars observations ii
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


Post agb stars
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



ad