[MODEST] a real start !

[Piet Hut]

Dear Colleagues, modest or not so,

it is a real pleasure for me to announce the first ever combination
of a stellar dynamics/hydrodynamics/evolution code, TRIPTYCH.  It is
extremely simple, but it runs!  And what is more, you can visit it on
a web site, enter your preferred parameters, and let two stars collide
dynamically and hydrodynamically, and watch the merger product evolve.

And yes, it is extremely simple.  Jamie Lombardi took his hydro shortcut
code, and sandwiched it in between a simple dynamical orbit integrator
and the stellar evolution toy model that Jun Makino and I wrote and put 
up on the MODEST web site, soon after our workshop.  But the main point
is: it is a real start, the first realization of what we talked about
for a week at AMNH in New York City, two months ago.  The next step will
be to replace both the dynamics and the evolution part with something
more interesting.  Steve McMillan and Jamie are discussing adding the
starlab three-body scattering package, to allow three stars to dance
and collide, and Jamie will also contacting Onno Pols, Attay Kovetz and
Dina Prialnik, as well as David Arnett, to see whether their stellar
evolution codes can be made to work in the slot of the current toy model.

As for the interface, Vicki Johnson has worked closely with Jamie over
the last week or so, to produce a spectacular user-friendly interface
to TRIPTYCH.  Vicki is a software consultant who has recently completed
an nbody project using a GRAPE card at Pomona College, with initial help
from Peter Teuben.  She runs her own business, Interconnect Technologies
Corporation.  Links to her activities can be found on the MODEST web site,
together with links to TRIPTYCH.

So far me introduction; below is the official announcement.

Piet

We are pleased to announce the release of TRIPTYCH, a computer program
that simulates the collision of two stars, including their orbits and
the stellar evolution of the collision product.

TRIPTYCH can be run via a web interface (see
http://143.229.45.51/cgi-bin/astro/triptych/triptych.pl )
and the source code is freely available (see
http://faculty.vassar.edu/lombardi/triptych/ ).

TRIPTYCH is a first step toward realistic dynamical simulations of star
clusters that include stellar collisions and stellar evolution. 
Currently, TRIPTYCH treats the dynamics of the two parent stars with a
simple Runge-Kutta integrator, the hydrodynamics of the collision with
a newly updated version of Make Me A Star (MMAS), and the evolution of
the collision product with a "toy model" stellar evolution code.  The
goal behind TRIPTYCH was to produce something fairly simple that worked,
so that a concrete framework existed upon which a more accurate,
detailed and robust code can be developed.  The hope is that people
will be encouraged by what they see and like --- and they will be
stimulated to improve what they see but don't like.  Certainly a
number of improvements can and should be made.  For example, MMAS
needs to be replaced with a more general collision module that, among
other improvements, allows for the possibility that the two stars do
not merge upon contact.  Further, the stellar evolution code should be
replaced with one that uses the full structure and chemical composition
information provided by the collision module. 

Check it out!  We look forward to your comments, suggestions and
especially improvements.

Sincerely,
Piet Hut
Vicki Johnson
James Lombardi
Steve McMillan
Peter Teuben

P.S.: from Merriam-Webster's dictionary:

Etymology: Greek triptychos having three folds, from tri- + ptychE fold
Date: 1731
1 : an ancient Roman writing tablet with three waxed leaves hinged together
2 a : a picture (as an altarpiece) or carving in three panels side by side
  b : something composed or presented in three parts or sections;
      especially : TRILOGY