From jmc@phobos.caltech.edu  Tue Nov  2 11:33:37 2004
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Dear Collaborators,

Below is the proposed outline for the HD 12039 paper that has been
discussed between Dana, Dean, Michael, and myself. The goal is
to produce a paper in relatively short order (by the end of the month).
If you would like to help in this effort, please send me a note
and let me know which section you would like to help with. Thanks!

John


Proposed outline for HD12039

I. Introduction
    --- General description of the debris disk phenomenon,
        and why it's important
    --- The quest for "warm" zodiacal clouds like our own
    --- These "ring world systems" suggest a dynamical shepherding
            of debris by planets (slightly different than the usual
            clearing by planets arguments)
    --- Previous examples: HR 4796A (but it's an A-star, and a binary)
            The infamous HD 98800 (but it's a two binaries)
            Dana's object (but it's a binary)
            zeta lep (but it's another A-star)
    --- "Herein we report the discovery of a debris system
         (around an isolated solar analog star) that has
         characteristics analogous to our own zodiacal dust
         cloud as it may have appeared in its early development."
    --- Description of HD12039

II. Observations
      --- Summary of IRAC/MIPS/IRS data
      --- references to the second FEPS data release

III. The circumstellar disk
      Goal: Demonstrate IR excess is real given quoted SSC uncertainties.
            This is done by showing HD 12039 is an outlier relative to 
            the other 32 sources in the FEPS data release.

      a) Plot color-color diagrams for FEPS second data release that show 
         source is an outlier.
      b) Plot IRS spectrum for HD 12039. and compare it with median/dispersion
         for the remaining 32 sources, again showing it is an outlier.
      c) Plot spectral energy distribution.
             Top panel: optical/ir photometry, best-fit kurucz model, and
                        IRS spectrum.
             Bottom panel: Residuals after subtracting Kurucz model

IV. Disk model
      Goal: In the context of a disk model, constrain simple properties of the
            disk using either DDS or a modified version of Dana's toy model.

      a) Adopt a basic model as follows:
         --- uniform disk between radius R1 and R2 with surface density Souter
         --- uniform disk between radius R* and R1 with surface density Sinner
         --- a single particle size, a
         --- a "default" dust composition

      b) For a given particle size, run a grid model models that vary R1, R2,
         Souter, and Sinner. Compute the chi-squared between each model and
         the observed IRS excess and the 70um point. The other data points will
         not provide any useful constraints. From the chi-squared values,
         compute the corresponding probability distributions for each of the
         parameters. My guess is that for a given particle size, R1 and the
         ratio and Sinner/Souter will be reasonably well constrained, but
         that is a guess.

      c) Repeat (b) for a different particle size.

      d) Plot then various quantities (rinner, annulus width, sinner/souter) 
         as a function of particle size to show the range of possible 
         solutions. The goal is place quantitative constraints on the density 
         contrast in the disk, the inner radius, and the annulus width.

      e) This is a straight forward excercise, but there are a few 
         complications that I anticipate:
         --- the grid search should be done in logR space and possible log S
         --- Maybe instead of adopting a single particle size, we adopt a fixed
             exponential distribution but vary amin.

V. Discussion and Summary
      Various comments about what to include here:
         Dean:
            I would then go back to the whole question of zodiacal dust 
            clouds and how you can make a ring of dust dynamically 
            (no Puppeteers here please).  Also, we have to discuss the
            current frequency of these zodi systems (including the results 
            from the IPAC/SSC folks on IRAS -- I forget the exact authors at 
            the moment, but Chas is the driver).   This feeds back into the 
            production of our own zodiacal dust cloud and nature of asteroid 
            belt.
         Meyer:
            We really need to assess, assuming there is not gas in the 
            system, whether or not the dust dynamics are dominated by 
            collisions or not. If so, there are ways to produce a large inner 
            hole by having collisions continue to erode particles to a size
            small enough to be blown out by radiation pressure (here
            probably 0.3-0.5 microns I would guess).  In a system highly 
            dominated by collisions, PR drag may note play a role. 
         Dana:
            Also, how does it compare with wild speculation about our solar
            system at that age.

            I think we can also compare with my toy models of the Kuiper Belt 
            evolution and Scott Kenyon's less-toy models of the same thing, 
            to see if our system would have shown a cold excess while showing 
            a warm excess to this extent. We can make statements about the 
            relative pace of evolution in inner and outer planetary zones.