Plan

  1. About the simulation zone. The physical size of the current simulation has . However, the hydrodynamic behavior suggest that the gas will go out further and will take a long time to fall back. I estimate that a minimum physical size would be for and binary separation. The simulation zone may still need to be larger for and separation. The physical size of the finest cell should be or less. Therefore, a 4 level AMR with base grid can handle the simulation. The time should take (estimated) more than 15 days on 120 cores (3 level AMR is 5 days). If I can run with 2*120 cores on bluehive. I think the simulation can be done by the end of August.
  1. The pulsation period is 1 yr. This is the highest macroscopic frequency in this simulation (compared to orbital period and/or any other). To resolve the mass loss rate, I need at least 8 outputs per pulsation period. Therefore if the simulation is 300 years. The output will have 2400. Each output will take 200 MB at least. So the total disk space needed for one simulation is at least 500 GB. Currently I have 1200 GB on bluehive.
  1. Run a 4au simulation with high resolution. 96au*96au*48au

Comments

1. Jason -- 8 years ago

With the current simulation parameters, the 3 AU run has very strong tidal forces, at least enough to deform the primary and yield mass-loss rates that should be above what we have in the simulation. But that’s for a mass-ratio of 0.5. So one possibility would be to use a lower-mass companion in the simulation. At 3 AU we should be okay if we stay below q~0.1 which would mean using a 0.1 M_sun companion instead of 0.5.

2. Zhuo Chen -- 8 years ago

Hi Jason,

In 3 AU simulation, the tidal force should be approximately 10% of the AGB star's gravitational force at the AGB star's surface. I will run a q=0.1 simulation after the 4 au simulation.

3. blackman -- 8 years ago

Hi: looks good —(I did now see the simulations for both 3AU and 4AU) a few comments/questions

1) In the R_d formula if tau → large R_d → small. is there a limit of validity implied here? 2) it is interesting to assess if there is any configuration where RLOF can be captured even when tidal forces are excluded. To assess this, I think one way is to replace d with the orbital separation that corresponds to the primary filling its Roche lobe and then see what parameters are required for the ratio to remain small.. -e

4. blackman -- 8 years ago

Hi So i just did the estimate i suggested and indeed if one lowers the secondary mass enough one can get RLOF with weak tidal force. i think it makes sense physically… -e

5. Zhuo Chen -- 8 years ago

Hi Eric,

I think it would be interesting to run a q=0.1 d=3AU simulation. I will create a table that we can discuss future possible runs.