" PHOTOEVAPORATION OR PLANETARY-MASS OBJECT AS THE ORIGIN OF THE INNER GAP  IN THE DISK OF RX_J1852 " 

We can change the title depending on which mechanism we will find is more probable for this disk

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OUTLINE

I would like to investigate whether the inner gap in the disk of RX1852 can be caused by photoevaporation or some mechanism related to planet formation is required. 

- We can use the [NeII] detection + Mdot to get an estimate of the UV field
  (we have also an estimate for Lx from which we can see how much X-ray would contribute
   to the [NeII] emission)   

- From the SED modeling we will get an estimate of the disk inner radius
  and of the mass in the outer disk (for this John has also resolved mm data!)

- Given the UV field, inner radius, age of the source and mass of the outer disk we should
  be able to see if photoevaporation can clear out the inner disk region

- If not, we can discuss other mechanisms related to planet formation and suggest which   
  other data could help to discriminate between the different scenarios.

- As an appendix we could try to explain why we did not see [NeII] in the other optically thick   
  disks from FEPS


Paper draft outline (comments are welcome!)

 1.INTRODUCTION: 
   - Place transition disks into context, what can we learn from transition disks?

     *   Here I would like help from Joan and S. Strom who were already thinking about this


 2. OBSERVATIONS: 
   - We will describe which observations we have:
     IRS spectra, optical spectra, mm data and a summary SED
     maybe TEXES data
    
    * Lynne - optical spectra  
    * IP, DW - IRS high-res 
    * for the data reduction of IRS low-res, IRAC and MIPS I would refer to the respective papers
      and only report a table with the photometry
    * John C. -- mm data ?


3. IMMEDIATE RESULTS FROM THE OBSERVATIONS

    *  Mdot  -> J. Muzzerolle is working on that
    *  line flux from [NeII] -- other line flux upper limits -> IP
    *  John C. : disk outer radius, disk mass from the mm interferometric data? Who else?
    *  Estimate of the gap from the SED, better disk models than C&G -> IP + C. P. Dullemond?

    
4. THE PHOTOEVAPORATION MODEL
   - In this section we will investigate if the inner gap can be produced by photoevaporation

    *  Estimate of the UV luminosity from the [NeII] -> David and Uma
       (maybe we can first have the simple analytical calculation and then the gas models)
    *  Comparison of our disk to the photoevaporation models from Alexander -> IP, David, Uma, Joan, and
       who else is interested in helping 

    
5. DISCUSSION
   - We will discuss if the photoevaporation model could work in this case or other mechanisms are required
     * All



7. APPENDIX
  - We could try here to understand why we did not detect [NeII] in the other 5 optically thick disks.
    Or shall we defer this discussion to another paper?
     * All