Galactic Model and Variable Star Characteristics
            ================================================

                         People most concerned:
 G.Bono, P.De Cat, M.Chadid, J.Fabregat, M.Groenewegen, P.de Laverny,
       P.Mathias, C.Neiner, A.Robin, L.Szabados, G.Wahlgren


BESANCON GALACTIC MODEL:
=======================

It has been pointed out that there should be a parallel development
between the
                Besancon Galactic model
and
                the variability analysis (for now GDAAS).

So variable stars should be implemented in the Galactic model.

In September a meeting was held between Annie Robin and Laurent Eyer in
Besancon.

Annie needs from the group members the following information:
   Given a stellar population (temperature, gravity, metallicity)

     1) what is the fraction of variable stars (of a certain type)?

     2) What is an available representation (templates of light curves)?
        With, for instance, distribution of amplitude and period for this
        specific population.
        If periodic, for example, the coefficients of the Fourier series
        could be given (with a distribution). To start with, a very simple
        model is required.

Two other general types of variability were not discussed at the meeting:
 a) The question of microlensing events, eruptive and cataclysmic variables.
    They have not been touched yet (except Be and RCB). Question: Is it for
    Science Alerts WG?

 b) The question of eclipsing binaries: Annie Robin said it will be
    treated by the Binary Star Working Group, including the aspects of
    eclipsing binaries. There are quite large discrepancies between
    the estimations on eclipsing binaries, what actions should the VSWG
    take for eclipsing binaries?

To accommodate this new information we can simply add a section in the
Variable Star characteristics documents.
I would suggest that this new section be placed just after the section
   "Number of stars known".

VARIABLE STAR CHARACTERISTICS
=============================

So we can update the documents (for some, that will be the third
iteration) on
   http://obswww.unige.ch/~eyer/VSWG/varchar.html
For the template see:
   http://obswww.unige.ch/~eyer/VSWG/VARCHAR/spb.txt
And ADD one section in order to put the information of fraction of
variable stars and a model.
As said, I would suggest just after the section
   "Number of stars known"


Commitments:
-----------
 - Martin Groenewegen agreed to do the work on SARVs
 - Merieme Chadid agreed to do a text on RV Tauri stars
 - Glenn Wahlgren on roAp and ACVn stars
 - Philippe Mathias with Ennio Poretti on delta Scuti stars
 - Guiseppe Bono on EC 14026 stars (?)

For all others, could you please update your document with the additional
described section.

If you have a task that you do not want to perform, or that you have been
forgotten, please write to Laurent. If there are some types of variable
which are not listed and should deserve attention, write to Laurent. If
anything is unclear, again write to Laurent!

Best Regards,
Laurent & Dafydd

The 13 of October 2004