Using UBOX files to change body parameters dynamically during a simulation.

[Shiolle]

Hello,

I'm sorry if this has been asked before, but I couldn't find anything relevant via search.

I want to do the following: on the Solar System simulation reduce the mass of the Sun gradually over 100 years until it is 1/10th of the original, and at the same time period increase the mass of Jupiter until it is 4 times as heavy as the original. It would be ideal if both bodies maintained locked density, so that their raidus changed appropriately.

I've tried to look into xml file format for clues how to achieve this, but it looks like it the file format only sets up the simulation. Is it possible to do what I described?

Thank you