system architecture

[SophieBudzik]

Hi!
I'm wondering how to define the system architecture if the lens is probably a binary brown dwarf. Should I define it as two planets or two stars?
Thanks for help

[jdeast]

Good question -- I haven't considered that.

One must be a star, as that's the only thing that carries ra, dec, distance, etc. Note that the lower limit on a "star" mass is twice the mass of Ceres, as the intended path to model Free Floating Planets.

But that might be problematic because of the IMF prior on mass. You can choose between a Free Floating Planet prior (currently MOA's, but that was something I planned on discussing with Radek, as I have a vague recollection that it is untrustworthy), Chabrier IMF, or Salpeter IMF. You can tune the coefficients of the FFP power law, but you can't turn it off. I'll add that to the to do list. If you have a strong constraint on their masses, it shouldn't matter much.

The other object probably doesn't matter whether it's a star or planet, unless you want to apply an IMF mass prior (star).

I think it'll work, but you're in a new and unanticipated regime (with a WIP code), so use with skepticism. I'm happy to help you model this and make any changes it takes to get it to work, so please ask follow-up questions (and post your results/success when you have it!)