COMMON ENVELOPE SIMULATIONS

Summary of last two weeks' work

  1. Running simulations:
    1. As Model A of Paper 1 but with
      1. ½ secondary mass (mostly complete) [Run 149]
      2. ¼ secondary mass (half completed) [Run 151]
    2. RLOF tests (partial runs, complete, need to analyze output)
      1. Separation of 109 Rsun, equal to Roche limit separation [Run 160]
      2. Separation of 73.5 Rsun, equal to 1.5 times the separation of Model A of Paper 1 [Run 161]
      3. Separation of 109 Rsun, with ambient density 10-10 g/cc instead of 6.7x10-9 g/cc [Run 162]
    3. Convergence tests for resolution and softening length (3 partial runs, each about half completed) [Runs 152, 153, 154]
    4. Convergence test for max refinement volume (full run, half completed) [Run 163]
    5. AGB test run (Pending) [Run 164]
      • Box is the same as Model A of Paper 1
      • AGB has radius 122 Rsun (instead of 48 Rsun for RGB)
      • Primary mass 1.8 Msun (instead of 2.0 Msun)
      • Primary core mass 0.53 Msun (instead of 0.37 Msun)
      • Secondary mass 1.0 Msun identical to Model A of Paper 1
      • Initial separation 124 Rsun
      • Refined out to radius 1e13 cm= 144 Rsun (instead of 5e13 cm= 72 Rsun)
      • Reduced the resolution to maxlevel=3 (from maxlevel=4)
      • Chose ambient pressure P_amb=104 dyne/cm2—-expect to resolve scale height at surface
      • Chose ambient density rho_amb=10-9 g/cm3—-compare to surface density of 4x10-9 g/cm3
  2. Working on Xsede proposal:
    1. Decided that the main objective should be to run a simulation with an AGB star
      1. 8 times bigger box but degrade ambient resolution by the same factor
      2. Might have to refine only core of AGB and surface shell of AGB at maxlevel
      3. Hydrostatic atmosphere that matches to a uniform pressure-uniform density atmosphere at a certain radius, to avoid larger ambient density/pressure
    2. Could explore dependence on secondary mass again
    3. And/or could try 3-body problem
    4. Use about ¼ of time to do convergence tests
  3. Plan for papers (not including work on recombination and dust led by Amy):
    1. Energy/envelope unbinding paper (November)
    2. Jets (~6 months)
    3. Dependence on secondary mass (~9 months)
      1. Energy and envelope unbinding
      2. Drag force
      3. Convergence tests
    4. Simulation with AGB star (~12-15 months)
      1. Energy and envelope unbinding
      2. Drag force
      3. Comparison with RGB simulations
      4. Possibly dependence on secondary mass (if resources permit)
    5. Three-body problem (if resources permit)
    6. RLOF or RLOF+CEE with RGB/AGB (let's see)

Ivanova+2013 equation 3:

New equation suggested by us:

Run 143 (Model A of Paper I) has initial separation . The Roche limit radius for as in our case is .

Run 164 (AGB) has initial separation . The Roche limit radius for the same secondary mass as in the RGB run is .

Then at what value of should the envelope be completely unbound, for a given value of ?

RGB (lambda=1.3)
Ivanova+2013 with
Ivanova+2013 with
New equation with
New equation with
AGB (lambda=0.9)
Ivanova+2013 with
Ivanova+2013 with
New equation with
New equation with

So the final separation needed for envelope removal is almost 4 times larger for the AGB!

Note also that the final separation is roughly given by the following asymptotic formula ():

,

where . This formula also says that should go up even more if we make larger.

But it might take a lot longer to get there than for the RGB case. We need to estimate how long it would take in simulation days from the preliminary test run 164 and also from analytic estimates (I will try to do this today). We will use this estimate to set what computing resources we ask for.

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