accretion configuration
This is a spin off of #504 (comment 14141)
struct MassTaper {
real accretion;
real start;
real final;
struct Taper {
real start;
real final;
};
if we put accretion (I suppose this is the parameter AccretionTimeInverse in the actual version , is it?) in MassTaper we should also add AccreteOntoPlanet
In the actual master version we have:
AccretionTimeInverse
in PlanetarySystem { Planets { BigEart {
and AccreteOntoPlanet
in PlanetarySystem
Now let's see how all this works:
-
Growing a planet by MassTaper is a controlled way to growth a planet and it is done in order to gently perturb the disk. It is especially useful in the case of giant planets. It can be used together with AccretionTimeInverse in point a below.
-
AccretionTimeInverse is used in 2 different ways:
a) in order to remove gas in the planet vicinity: this is useful to avoid the production, at gap's edges, of strong bumps in the gas density distribution. Such bumbs would go away only on a viscous timescale.
b) to let the planet accrete gaseous atmosphere in a self-consistent way: the gas in the planet vicinity is added to the planet mass (as well as the angular momentum). It can be used together with MassTaper if the user wants to.
a) AccretionTimeInverse different from zero and AccreteOntoPlanet == false
In a region of size 0.6R_{H}
( R_H
the Hill radius)
the gas density is reduced at a rate
\rho(t) =\rho_0\exp (-t/\tau _{acc})
with \tau_{acc}
the
depletion timescales, 1/\tau_{acc}==
AccretionTimeInverse
We do not add here the mass (and angular momentum) removed from the gas to the planetary mass.
b) AccretionTimeInverse different from zero and AccreteOntoPlanet == true
We use the above recipe but we add to the planet mass and planet velocities the mass and angular momentum/(planet mass) removed from the gas
Is it more clear ?