Update 06/24

CEJet

Working on branch ticket_442.

Questions to answer for jet project:

  • How does the jet affect the morphology of the envelope?
  • How does the jet affect the ejection of the envelope?
  • How does the jet evolve, does it get quenched?
  • What is the dependence of these questions on when the jet gets turned on?
  • What is the dependence on accretion rate?
  • Opening angle?

movies from test run 44

Starting with secondary right against the primary envelope. No secondary mass. Jet mass loss rate at 2 M_sun/year, and radial velocity 430 km/s (Keplerian).

​density-edge-on ​temperature-edge-on ​density-face-on

3 test runs planned for this week:

4 levels of AMR with 64 base grid resolution. Each run is planed for 10 days in simulation time, and takes about 2 days to complete on bluehive.

  1. [Run 45] Secondary starts right against the primary envelope: a0 = 49 R_sun.

Use lower ambient density and pressure profile: rho_amb = 1e-10 g/cc, p_amb = 1961 dyn/cm2 .

  1. [Run 46] Secondary starts right against the primary envelope: a0 = 49 R_sun.

Use ambient profile as the CE fiducial run (run 143): rho amb = 6.67e-9 g/cc, p_amb = 1e5 dyn/cm2

This and the first run will compare the effect of ambient material over the jet. Also a comparison with the CE fiducial run.

  1. [Run 47] Start with the secondary farther out: a0 = 72.5 R_sun, and use lower ambient profile.

There is also a CE run without jet to be compared.

Some parameters to explore

49 R_sun, right against the primary envelope. Jet might be quenched after the secondary enters the envelope.

72.5 R_sun, start farther out, longer time for the jet to evolve (although farther means lower mass loss rate if we use accretion rate to determine the mass loss of the jet).

109 R_sun, Roche distance of our system.

  • Jet mass loss rate

From CE paper 1, the secondary can have extremely high accretion rates of ~ 0.2 - 2 M_sun/year. This rate corresponds to 100 - 1000 times the Eddington rate for a MS star, or 1e4 - 1e5 times for a WD.

Currently we are using the upper limit (2 M_sun/year). For a more physical value, we plan to compare between 1 vs 100 times Eddington rate of a WD (100 times WD rate would be ~ Eddington rate for a MS).

Check out the Xsede proposal for more suggested tests.

  • Jet radial velocity

​Federrath+2014 suggests using Keplerian velocity at the surface of the star.

In the current test runs, this is computed using initial mass of the secondary (0.978 M_sun), and 1 solar radius. So,

jet_vrad = sprt (G*M2/R_sun) = 430.75 km/s

  • Jet radius, distance from the secondary particle within which the jet is initialized. 64 cells (70.4 R_sun) for now. Federrath+2014 also tested this effect, and suggests using 16 or 32 cells.
  • Refinement radius (compare to the orbit). See CE paper 1 fig. 3, and paper 2 appendix fig. C1.
  • Refinement shapes and qTolerance.

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