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Bondi update - April 30
Two Bondi runs: gam=1.0001, gam=1.4
In each case, the Bondi radius (GM/cs_inf2) is resolved by the same number of zones (~160).
Gam=1 doesn't blow up, but gam=1.4 does. It seems this can be attributed to adiabatic pressure increase in the kernel (due to mass pile up) that sends out a shock wave upstream into the Bondi flow. Does the pressure increase in the kernel support this?
Movies are here:
gam=1.4
Density: gam1pt4_rho.gif
Pressure (ram vs. thermal): gam1pt4_press.gif
Speeds (sound vs. vmag): gam1pt4_speeds.gif
gam=1
Density: gam1_rho.gif
Pressure (ram vs. thermal): gam1_press.gif
Speeds (sound vs. vmag): gam1_speeds.gif
A comparison of the density and pressure at frame 0 and 1 for the different gamma cases is here:
And pressure is here:
These are the same physical time. I think the dynamical time is set by the gas properties at infinity, in which case these should also be the same dynamical time…
Lastly, mdot converges to its theoretical value in the gam=1 case, but not gam=1.4 case:
The Bondi and accretion algorithm mdots are calculated from different expressions. Classical Bondi mdot is:
whereas the Krumholz prescription uses:
Update 4/30 (Radiation Pressure)
WASP-12b paper accepted - will be posting to ArXiv today.
Radiation pressure:
All of the following are in computational units:
For and , white is .
Cross-cut
Ly- flux for HD209458b
From here (Bourrier & Lecavalier des Etangs 2013), flux peaks at J = ~28x10-14 erg cm-2 s-1 AU-1.
Converting to photons cm-2 s-1,
Which is 3 orders of magnitude less than the maximum flux in our simulation. If instead it should be scaled to the orbital radius (0.04747 AU, not 1 AU), that reduces it to 1.2x1010.
Timescale for blowoff vs. replenshiment
Assume torus of axis AU, radius of cm, and uniform density g/cm3. Given the mass loss rate of the planet, the timescale for replenishment is:
s
The timescale for blowoff is dependent upon the gravitational binding energy and the energy deposited by photons on the edge of the torus per unit time:
erg
erg/s
s
Progress
- Ionized parker wind with recombination. X=0.7 Y=0.3, therefore is fully molecular state and is the fully ionized hydrogen and molecular helium state.
- I am writing the code that solves the 1D Eulerian radiation hydrodynamics with flux-limited diffusion radiation transfer combined with ray-tracing radiation transfer and a general equation of state hydrodynamics. It will also have dust formation, frequency dependent radiation transfer, and dust destruction. I have successfully combined the two radiation transfer method in optically thick and optically thin region. One week away from the completion of the code.
Update 4/23
Radiation Pressure
Side
Top
Shadow recombination
Recombination rate 15000;
Recombination timescale
Update 4/16
Paper
- Run5 done:
- Non-rotating results and rotating run 1 results done. Need to discuss 2 further and write about 5 and 6.
- Want to get a good start on the discussion this week. Any sections I'm missing from the current outline?
Radiation Pressure
- 2d14 almost done. 2d15 crashed - I suspect everything's just been violently blown away, but VisIt keeps crashing every time I try to make visualizations of these. I'll try to figure that out this afternoon.
COMMON ENVELOPE SIMULATIONS
New Work
- Updates to the paper
- New movies corresponding to figures in paper
Update on Paper
Here is the pdf so far.
- Address comments
- Decide the way forward.
- Next paper?
Movies corresponding to figures in paper
Figure 1:
Face-on density (Model A no sub-grid accretion)
Figure 2:
Face-on density (Model B Krumholz accretion)
Figure 4:
Edge-on density (Model A no sub-grid accretion)
Edge-on density (Model B Krumholz accretion)
Edge-on density (zoomed in) (Model A no sub-grid accretion)
Edge-on density (zoomed in) (Model B Krumholz accretion)
Figure 6:
Tangential velocity with velocity vectors (Model A no sub-grid accretion)
Tangential velocity with velocity vectors (Model B Krumholz accretion)
Update 4/3: Wind Tunnel Run008 (ongoing) & some plots of WT007
Ongoing Run
WTRun008
Initial condition: at 4*1012 cm of a 3M_Sun AGB star. Mach number = 2.5, rho = 3.6*10-6. Simulation Setup: the same with Run006, with region of highest resolution R_max = 30CU, Softening length (spline) is 4CU, resolved by 16 pixels.
Some plots on Run 007, will type up a note further explaining notations.
Orbital Decay vs Time
Growth of Bondi-Hoyle Radius
Acceleration, constant scale
Acceleration, scale to instantaneous BH rate
Acceleration vs. Mach
