CEJet

• Now the tracers work correctly tracking the primary envelope, ambient, and jet material.
• Do the three remaining runs this week.
• Plot orbital and energy info when bluehive comes back.

Rad hydro - reading

• ​Krumholz+2007
• ​Ensman 1994

Movie Night! (07/29, 7:30PM)

​Vote here if you haven't voted yet.
As of now we have a two way tie for first place.

1. Hitchhikers Guide to the Galaxy
2. Inception (tied for first)
3. Forbidden Planet

Fermi Project

Goal: Figure out how to make the probe velocity and range normally distributed within our FORTRAN model.
​Click here to see the PDF which summarizes my progress so far and my next steps.

Current Model Output (Colored by Technology, Pink=Unsettled)

Coupled EBM

Parameter Sweeps (20 different temperatures and distances)

Contour Plots ​(Earth-Like Values)

KDE Plots

Objectives

• Continue testing & debugging
• Work on Grain-Grain Collisions

Progress:

• HPC Proposal: This is finished for now, the next phase will be in September.
• Debugging: Ongoing benchmarking using external processing.
• Grain-Grain Collisions: See the pdf ​here!

Up Next:

• Need to look some more at the fragmentation case
• Continue with benchmarking

EoS stuff

Work done

1. Plotted pressure and temperature profiles from frame 0 of simulation and compared with previous results.
2. Plotted sound speed profile from frame 0 of simulation and compared with that of fiducial RGB Run 143.
3. Plotted free electron fraction, gamma1 and mu profiles from frame 0 of simulation and compared with MESA profiles.
4. Added gamma3 (MESA) to plot from last blog showing gamma1.
5. Planning for Paper 5 on EoS.

Results

1. Initial conditions
   1. The ​pressure profile from frame 0. Orange=Run 143 (fiducial ideal gas EoS), Green=Run 207 (MESA EoS). Profiles match perfectly, as expected (pressure profile was inputted in a data file).
   2. The ​sound speed profile from frame 0. Red=Run 143 (fiducial ideal gas EoS), Black=Run 207 (MESA EoS). Profiles are slightly different. Consistent with P and rho profiles being the same between simulations, but gamma1 differing. Since c_s propto gamma1^½ and gamma1 reduces by no less than a factor of about 4/5, we get no less than a factor of about 0.9 in c_s. So the difference in c_s profiles is very small.
   3. ​RGB Pressure profile from MESA. As shown in the last blog but now with the new curve showing the simulation initial condition.
   4. ​RGB Temperature profile from MESA. As shown in the last blog but now with the new curve showing the simulation initial condition.
   5. ​RGB Various profiles from MESA. As shown in the last blog but now with new curves for electron fraction, mean molecular mass mu and gamma1=(dlnP/dlnrho)_S showing the simulation initial condition.
   6. ​Yisheng's plot of initial profile (temperature) in cgs units.
   7. ​Yisheng's plot of initial profile (specific internal energy) in cgs units.
2. ​Derivation of expression for mu in terms of X, Z, average number of nucleons per metal species A, and electron fraction
3. ​Plan for EoS project, presentation given during meeting

Discussion

• mu was computed using an analytic formula which assumes a mean atomic mass for metal species of 16 (the result is not sensitive to this number).
• It is not possible to compute the recombination energy (total or from each species individually)
• Since the hydrogen, helium and metals fractions are CONSTANT in the envelope (and are assumed to be constant for the duration of the simulation), then to compute mu we would need the ionization fraction of each species, e.g. n_HII/n_HI, n_HeII/n_HeI, n_HeIII/n_HeII, and the same for all the metal species included in the EoS.
• These ionization fractions can be estimated using the Saha equation but this would not take fully into account the EoS. This was the method used by Reichardt+2020 to compute the recombination energy—but they neglected ionization and recombination of metals.
• Can the ionization fractions for each species as well as mu be obtained directly as part of the MESA EoS? If not, we need to use the Saha equation.

Next steps

• Use Saha equation to estimate the ionization fractions and recombination energy and make some plots.
• Migrate new code to Stampede and test (produce 1 frame for each run).
• Prepare the new fiducial run (increased resolution, etc.) and new EoS run (Runs R1 and R2 in the Plan for EoS project presentation above), and perform test runs.

What do we have for the CEJet project

Runs:

Code:

• I'm testing the tracer on ambient. otherwise the astrobear_1008 version is good to go for the remaining runs.

code version	note
_1014_C	particle buffer on both P1 and P2
_1212	use Shape to define refinement region
_1008	updated to fix tracer on jet, good for stp_run_006 & _009
_0112	refine on density criteria

Analysis:

• Orbits, average separation plot. ——> working on the script
• Mass, bind vs. unbind, find a best way to present this. ——→ working on script to read the totals data file
  • maybe something like Fig. 8 in the AGB paper, where more mass gets elevated but still not unbind
• Energy, use data from the totals, do post-process if necessary
  • maybe analyze drag force as well, but orbit plot also shows the effect of drag force
• Present figures similar to the AGB paper
  • Fig. 6, 7, 8
• Update the separation plot
  • use CE run 152 for high mass fiducial, which doesn't change the softening radius

From thermal bomb meeting, 2020-7-16

Emily's new PN project:

• Inject for a brief period but strong energy into the outflow
• over free-fall / orbital time scale
• how much energy does it take to destroy the torus?
• calculate reasonable parameters for the CE binary used in my PN simulation (Emily)
• launch the wind with new parameters in the current PN module for ~6 days (free-fall timescale) (Amy)

○ pressure support for the central region after shutting down the outflow?

GEE reading notes

Soker (2020) "Shaping PNe with jets and the GEE"

General properties of jets in shaping PNe

1. Vjet ~ V_esc, MS V_esc ~ 600 km/s —> V_jet ~ (0.5~2) V_esc = 300 ~ 1200 km/s

2. Jets deposit energy + momentum by heating/expelling ambient —> less mass to accrete

negative feedback cycle —> quench/re-start —> many ejection episodes

3. "Pressure release valve" —> high accretion rates

positive feedback cycle

4. might have a wide open angle —> theta~90 degrees

GEE: companion grazes the giant envelope (~photosphere)

• BHL accretion of surrounding gas
• RLOF from inner dense envelope

ILOT (intermediate-luminosity optical transients)

(​https://phsites.technion.ac.il/soker/ilot-club/)

t_photon_diffusion .le. t_gas_expansion —→ large amount of E_th —→ Radiation lost

GEE forming SNe IIb

• SNe IIb = core collapse, almost no H
• jets remove H in the giant envelop during GEE
• jets are on the MS companion, the giant will end in core collapse SN

Five phases of Jets' launching —- companion launches the jets

1. Jets in wind accretion zone
   • Hillel+2020
   • P2 has jet before enter P1 envelope
   • BHL accretion from slow wind
   • Jets being dragged/bent behind, can't penetrate the accreting wind
2. Jets from pre-CEE RLOF accretion
   • equatorial accretion flow, RLOF mass gain much greater than that from BHL
   • jets penetrate (likely) the wind, form bipolar lobes/point-symmetric
   • can also occur earlier in wind-RLOF
     • Harpaz+1992
     • Mohamed+Podsiadlowski 2007

3. Jets during the GEE (too delicate??!)
   • Eta Carinae?
   • P2 accretes near periastron
   • BHL+RLOF
   • Shiber+2017

4. Jets during the CEE
   • BHL from inside the envelope
     • Shiber+2019
     • jets don't break out the envelope
   • what is jets' role in helping mass removal?

5. Jets during the post-CEE
   • P2 accretes from circumbinary disk
     • Soker2019, Kashi+Soker2011, Chen+Podsiodlowski2017
   • P2 launches jets w/ variable directions + intensities

Making Sense of Convergence Study

The plot of the convergence series was confusing

So, I made a couple of other plots focusing only on 1 case. Hopefully, this makes more sense.

Earth Magnetosphere

Imported SmoothDipole from PlanetaryOutflow module. Found SphericalRotation and InvSphericalRotation in CommonDefinitions to rotate the dipole and re-rotate the magnetic vector potential.

Still need to decide a few parameters. BlueHive stopped being cooperative during testing.

(Aside: Absolutely do no leave the tracer variable on for the physics module you just turned off..)

Box size? (Bow shock can extend upto 20 R_E for extreme solar wind values)

AMR Levels?

Moon Proposal Video

Need a video to go along with the proposal we submitted (not urgent). A couple of options:

1. xy density with field lines (too "jumpy")

2. 3D rotation of final frame (need higher resolution run?)

Quals (Progress Paragraph)

Comments on the email thread. Will send it to Laura today.

test

Putting in the MESA equation of state

Work done

1. Examined MESA RGB model (used as initial condition in our simulation) in more detail, including
   1. Temperature profile
   2. Free electron fraction profile
   3. Mean molecular weight profile
   4. Condition for convective instability as a function of radius
   5. Convective time scale as a function of radius

Results

1. Initial conditions
   1. ​RGB Pressure profile from MESA showing total pressure, gas pressure and radiation pressure. We see that gas pressure dominates outside the softening sphere.
   2. ​RGB Temperature profile from MESA. We see that outside the softening sphere the temperature is predicted accurately by assuming the gas to be ideal. Also, the temperature is higher than that obtained by assuming pure fully ionized hydrogen (mu=m_H/2), and lower than that obtained assuming pure fully neutral hydrogen (mu=m_H), except within 1 Rsun from the surface, where it is higher than both. The ionization temperatures of H and He are also plotted for reference.
   3. ​Graph showing gamma1 (adiabatic index) free electron fraction and mean molecular mass profiles from MESA. We see that gamma1 remains below 5/3 and dips below 4/3 near the surface. This behaviour is roughly predicted by an ​analytic model contained in these notes by G. Glatzmaier that assumes pure hydrogen, using the free electron fraction profile from the MESA simulation, shown in black in the plot. We also see that gamma1=(dlnP/dlnrho)_S is quite similar to the polytropic Gamma1=dlnP/dlnrho calculated for the stellar profile, which tells us that the envelope is probably convective. The electron fraction is fairly constant but dips after about r=30Rsun, which coincides with where mu increases. Finally we plot Del=dlnT/dlnP and the critical value of Del=dlnT/dlnP for (i) an ideal gas with gamma1=5/3, which gives (gamma1-1)/gamma1=2/5, (ii) the MESA simulation neglecting the compositional gradient (Schwarzchild criterion) and (iii) the MESA simulation including the compositional gradient (Ledoux criterion). The plots below zoom in on this region to show more clearly what is happening as per convective stability/instability.
   4. ​Graph showing condition for convective instability. This graph should be compared with ​Figure 6 (bottom left) from ​Ohlmann+2017. Our results are consistent with theirs as long as we use the Ledoux condition outputted from MESA directly. If we compute the compositional gradient dln mu/dln P from mu and P we get the red line instead of the blue line. I don't understand why, but anyhow, as we will see in the next graph, both lines are consistent in that they predict convective instability. The black dash-dotted curve would be the relevant curve for the fiducial RGB simulation with adiabatic EoS (gamma1=5/3). We see that for that simulation, the star is predicted to be convectively stable.
   5. ​Graph showing condition for convective instability, plotted in a way that more clearly shows whether profile is stable or unstable. We clearly see that for the Ledoux criterion (blue line), which is the relevant criterion in our case, we are convectively unstable everywhere outside the softening radius. Note that the red line should match the blue line, but doesn't for some reason (see above), but in any case the red line also predicts convective instability. So to summarize, we see that the profile is convectively stable if the adiabatic gamma1=5/3 EoS is assumed, but convectively unstable for the more realistic EoS, consistent with Ohlmann+2017.
   6. ​Graph showing convective speed from MESA model. We see that the typical convective speed is ~0.7 km/s, rising to ~1 km/s near the softening radius and steadily rising to ~4 km/s near the surface.
   7. ​Graph showing convective Mach number from MESA model. This can be compared with Figure 9a from ​Ohlmann+2017.
   8. ​Graph showing convective time scale computed from MESA. The convective time scale is computed either by taking H_P/v_conv where H_P is the pressure scale height, or H_P²/eta_MLT where eta_MLT is the diffusion coefficient from mixing length theory, outputted by MESA, or L_MLT²/eta_MLT where L_MLT is the mixing length outputted by MESA.
2. AstroBEAR results
   1. I ran the simulation up to 2 frames on bluehive. It slowed down by about a factor of 3 compared to the first frame. The reason is probably that the code was struggling to resolve the large gradients near the particles. The density reduced markedly around the RGB core particle between frames 1 and 2, which does not happen in the fiducial run. The velocity with respect to the RGB core particle points outward. Could this be caused by convection? Or is it just that more resolution is needed at the RGB core when the MESA EoS is used? (Note that inside the softening radius, the profile is the reconstructed profile, not the original MESA profile.)
      • ​Zoom-in on RGB core, MESA EoS Run 207
      • ​Zoom-in on RGB core, fiducial Run 143
   2. The gas profile around the secondary is quite different from the fiducial run.
      • ​Zoom-in on secondary, MESA EoS Run 207
      • ​Zoom-in on secondary, fiducial Run 143 Although it would be worth adding more resolution around the secondary, the difference seen is probably physical and likely has to do with the smaller gamma1 near the surface in the MESA EoS model. A smaller gamma1 means that more compression is required to achieve a given pressure, so we might expect greater density in Run 207, which is what is seen.

Summary

• Pressure is dominated by gas pressure.
• Temperature is as expected for an ideal gas.
• Adiabatic gamma = gamma1 = C_P/C_V (with C_P and C_V the specific heats at constant pressure and volume) = (dlnP/dlnrho)_S (at constant entropy), which is 5/3 for a monatomic ideal gas. Here we obtained gamma1 from MESA and find that it is close to the polytropic Gamma1 in the envelope (as expected for a convective envelope) except near the surface.
• We then used gamma1 along with the stellar profile, to compute Del-Del_Ledoux at each point, where Del=dlnT/dlnP and Del_Ledoux=(gamma1-1)/gamma1 +dln mu/dln P. We find the envelope to be convectively unstable outside the softening radius. For the adiabatic EoS with gamma1=5/3 as used in the fiducial model, we find that the envelope is stable to convection.
• Our results for convective instability for the adiabatic gamma1=5/3 model (stable) and also for the MESA tabular EoS model (unstable) agree with those presented in Ohlmann+2017 for their profile, which is very similar to ours.
• The convective time scale varies between a few days near the surface, to ~50-400 days in the bulk of the envelope, to ~10-50 days at the softening radius. Thus, we would expect the surface layers to be somewhat less stable than in the fiducial run during the dynamical plunge-in (about 12.5 days to the first periastron passage in the fiducial run). Futhermore, we would likely see more mixing inside of the particle orbit at late times in the simulation since the simulation time (40 days) is comparable to the convective time near the softening radius.
• More resolution is probably needed at the primary core.

Fermi Project

Goal: Figure out how to make the probe velocity and range normally distributed within our FORTRAN model.
​Click here to see the PDF which summarizes my progress so far and my next steps.

Current Model Output (Colored by Technology, Pink=Unsettled)

Coupled EBM

Comparing Experiments

dPdT: Amount of pCO2 that must be added to the atmosphere in order to change the climate by 1 degree Kelvin.

Experiment #1: Constant Composition (P0=284 ppm)

Experiment #2: Constant Temperature (T0=287.09 K)

Earth-Like Inputs

• t0=1820
  • We choose this because our data starts here.
• P0=284 ppm
  • This was the global CO2 concentrations during 1820.
• N0=1.129 billion people
  • This was the global population during 1820.
• Nmax=10 Billion people
  • This one is based on ​current trends and global projections
• dT=5K=Temperature Sensitivity
  • We chose this because it seemed reasonable in regards to what kind of temperature range humans can survive in.
• dP=200 ppm=Carbon Dioxide Sensitivity
  • Similar to dT, we choose this because it seemed reasonable
• A0=0.04 1/yr=Initial Per-Capita Birth Rate
  • We chose this based on the assumption that the average time for a generation is 25 years, so that A0=1/25=0.04 1/yr
• B0=0.036 1/yr=Initial Per-Capita Death Rate
  • We chose this value in order to tune our model to the data.
• C=0.000275 ppm/(10⁶ppl*yr)=Per-Capita Carbon Footprint
  • We chose this based on present-day values

Are these numbers reasonable?

The relevant quantity for how population grows is the difference between A0 and B0, this quantity is called the per-capita (net) growth rate. The relevant quantity for how CO2 concentrations change as a function of population growth is C, the per-capita carbon footprint. We can compare our models values against global values to determine how accurate our model is.

Exo3

Posters. Mine is supposed to be MHD, though it can still be edited. I think we may have gotten enough to make an interesting poster, though, especially with the last frame or two of the most recent run. Current plan is to discuss Eric's theory about the field guiding the wind in a more LOS direction in the context of original parameter space run and new results.

MHD tests

Truly uniform, constant magnetic fields. Initial conditions are the same in each pair of strong/weak field runs, barring the magnetic field strength. All simulations are using outflow-only boundary conditions.

Haven't run the simulations including a stellar wind yet, a little more difficult to double check the implementation of those.

+----------------------+------------+--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            |              | Strong Field (4.5x10^1^ G)                 | Weak Field (4.5x10^-4^ G)                                                                                                                                                      |
+======================+============+==============+============================================+================================================================================================================================================================================+
|                      |            | No wind      | Immediate pressure protections. No frames. | Runs well. Slight acceleration, moving at max of ~5 km/s at 21 frames. Possibly from boundary condition?                                                                       |
|                      | No gravity +--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | Stellar wind |                                            |                                                                                                                                                                                |
| Non-corotating frame +------------+--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | No wind      | Immediate pressure protections. No frames. | Runs well. Accelerates toward star, bending field lines. 20 frames.                                                                                                            |
|                      | Gravity    +--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | Stellar wind |                                            |                                                                                                                                                                                |
+----------------------+------------+--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | No wind      | Immediate pressure protections. No frames. | Runs well. Accelerates as expected, fixed at left & top because of boundary condition. 20 frames.                                                                              |
|                      | No gravity +--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | Stellar wind |                                            |                                                                                                                                                                                |
| Corotating frame     +------------+--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | No wind      | Immediate pressure protections. No frames. | Runs well. Accelerates outward (I think as expected? Orbital velocity of planet is higher than Keplerian velocity of ambient). 4 frames (for some reason only ran on 4 cores). |
|                      | Gravity    +--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                      |            | Stellar wind |                                            |                                                                                                                                                                                |
+----------------------+------------+--------------+--------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Images of runs, numbered in order of appearance in table above:

Run 2

Run 6

Run 10

Run 14

Charge Exchange

Solar-type wind crashed with MPI issues before completing a single frame. I've halved the number of cores to reduce the messaging, which should fix that.

Completed 3 (of 5 planned) frames of strong wind with collisional ionization:

Putting in the MESA equation of state

Work done

1. Modified my own version of the code on bluehive to incorporate changes made by Yisheng and Jonathan
   1. Substituted Yisheng's /scratch/afrank_lab/EOS/astrobear/src/objects/tables.f90, src/physics/EOS.f90, src/physics/abundances.f90, src/hyperbolic/riemann_solvers.f90 and src/module_control.f90 (the only change in the latter is to comment out the Jean's length refinement criterion), src/Makefile (only differences is that it changes the order of compilation of EOS.o and tables.o to avoid a compilation error).
   2. Other files kept my own: important differences include src/particle/particle_control.f90, where I comment out creation of new particles. Certain other files are different between our versions but I decided to keep my own: src/objects/ambients.f90 (not used by me anyway), src/particle/particle_info_ops.f90 (apparently recent changes were made to the Bondi-Hoyle-Lyttleton accretion rate algorithm, but this does not affect simulations where subgrid accretion is turned off), src/data/data_info_ops.f90 (new lines of code, not sure of significance), src/distribution/distribution_control.f90 (Intent OUT had been changed to INOUT for pointer newgrids—-not sure of significance), src/hyperbolic/sweep/sweep_declarations.f90 (small differences, not sure whether significant).
2. Compiled and ran the version of the code which was basically the same as Run 143 (fiducial RGB run) but with iEOS=6 in physics.data (tabular EoS) on BlueHive (110 cores, one frame of 2e4 seconds—same as for fiducial Run 143 which lasted 173 frames—takes about 24 hours). This run is called Run 207.
3. Analyzed the AstroBear initial condition from Run 207 to see if it agrees with expectations.

Results

1. Initial conditions
   1. The ​density profile from frame 0 of Run 207 is the same as what was inputted, as expected. Red=Run 143 (fiducial ideal gas EoS), Purple=Run 207 (MESA EoS).
   2. The ​internal energy density profile from frame 0 of Run 207 is different from that of Run 143, as expected.
   3. The internal energy density profile from frame 0 of Run 207 matches very well the internal energy profile directly obtained from MESA. See ​figure. Thus, the code passes this initial test!
   4. However, we see that there is an inversion of the internal energy density at large radius. This happens in the region where the pressure is almost constant (~1e5 dyne/cm2) and the density had decreased to quite low values (~7e-9 g/cc). Yisheng plotted the profile of specific internal energy (i.e. E_int per unit mass) in the rho-P plane, and found that the specific internal energy turns up at small density, which is consistent with what we are getting. See ​figure1 and ​figure2. We are not sure what causes this in the EoS, but it is not necessarily a problem. One could in principle get rid of it by using a lower ambient pressure (but this would require increasing the resolution near the stellar surface).
   5. ​mass fractions. The ratios of number densities of He and H and of metals and H are specified in physics.data. These are used to calculate the mass fractions X and Z and then the MESA EoS table with this X and Z are selected. I went over this calculation to make sure that everything is consistent. But what about ionization??
   6. ​free electron number and mean molecular weight per gas particle (ions + free electrons).
2. Simulation results
   1. Density profile for new run at frame 1 (0.23 d): ​whole star with mesh and ​zoom-in on secondary and ​zoom-in on primary core.
   2. Same thing but for fiducial RGB run 143: ​whole star with mesh and ​zoom-in on secondary and ​zoom-in on primary core.

Next steps

• Modify mu for ideal EoS since current choice of 2.21 seems too high. But we are mostly not in the ideal gas regime, so should not matter much if at all. Need to redo tables to reflect this change. Keep gamma=5/3 for ideal gas.
• Plot radiation pressure and gas pressure to get sense of contribution of radiation pressure (it will be small, but worth plotting).
• Better understand what is causing the difference between initial E_int profiles in MESA EoS and ideal gas EoS (latent recombination energy? radiation?)
• Get thermodynamic variables like pressure and temperature to be outputted in chombos and plot them; also compare with ideal gas case.
• Compute and output gamma
• Re-read Nandez+Ivanova, Ohlmann+2017, Reichardt+2020
• Putting recombination energy into our simulations

Plan

• What is the plan for this paper?
  • Convection?
  • Compare fiducial RGB run with MESA EoS RGB and recombination run?
  • Improve fiducial RGB?
  • Compare fiducial AGB run with MESA EoS AGB and recombination run?
  • Which analysis to do?
    • Unbinding
    • Orbital evolution
    • Energy transfer
  • Do we try to compute opacities, optical depths, and diffusion times to assess whether recombination energy can be thermalized locally, or just assume that it can be?

MHD

Still having issues with both the restart and the current fresh run.

The restart is starting properly now, but still has immediate pressure protections (not unexpected) and very high CFL to start, so it almost immediately freezes.

I'm trying to restart the fresh run from earlier frames with a higher diffusion coefficient. Running into the same issue with high CFL conditions, but this time it seems linked to the higher diffusion coefficient. Going back to an earlier frame reduces the equilibrium predicted wall time, but still trying to figure out where I need to go back to in order to get a reasonable value. Removing the maxsolverspeed helps with, but does not entirely solve, this problem. The pressure protections here are mostly in ghost zones, and pretty much entirely at various grid intersections.

Charge exchange

Solar-type wind going slow, pretty much as expected. Should speed up as the shock relaxes. But appears to be running well.

Notes on EAS CE conference held July 2-3, 2020

• Morgan MacLeod's ​CE bibliography. He says you can email him to suggest more relevant papers.
• Worth checking out Paul Ricker's talk for his implementation of flux-limited radiative transfer: [recording ​https://portalapp.kuonicongress.eventsair.com/VirtualAttendeePortal/eas-annual-meeting-2020/virtual-eas/] but I'm unable to view it, possibly because I was a speaker during that session? Anyway, my notes say that his radiative transfer algorithm triggers on temperature gradient. He uses OPAL opacities. He says that a challenge of their simulations is that energy is trapped closer to the star than what may be realistic.
• During my talk there was a question by Friedrich Roepke about AM conservation. We should measure it for the next paper.
• Christian Sand's talk on CE with AGB star: gets 7.4 to 9.4 years ejection if recombination energy is included. Does not get enough unbinding with ideal gas EOS but not clear whether extra unbinding is caused by recombination or the difference in the initial profile between ideal gas EoS case and the OPAL EoS case (I think they use OPAL rather than the full MESA EoS). They think it's the recombination rather than the initial profile that makes the difference but have not done a test to confirm this. Both Paul Ricker and I were wondering about this.
• David Jones: mass transfer could happen before, during or after CE phase. Since main sequence companions are almost always observed to be inflated (by up to 3 times), sometimes mass transfer may get reinitiated at the end of the CE phase (speculative). But worth thinking about. Would RLOF occur at the end of the simulation if the companion gets puffed up? Or would the secondary get tidally shredded?
• Wouter Vlemmings: water fountain sources with high Mdot ~ 0.01 to 0.1 Msun/yr outflows, M_torus ~ 0.2-1.3 Msun. Estimate initial mass of system is ~ 1.4-2.4 Msun, so we are talking about low mass stars. I think it might be possible to explore these systems with CE simulations.
• M. Santander-Garcia: Their hypothesis was that post-CE PNe should be more massive compared to non-post-CE PNe. They find confirmation of this at what he feels is a somewhat marginal level (~0.24 Msun for post-CE and ~0.17 Msun for regular sample). What he says is that a more interesting result is obtained when the post-CE sample is separated into single degenerate and double degenerate. DD have larger mass ~0.63 Msun compared to SD ~0.15 Msun. Something to think about.
• In the discussion following Amy's talk Noam was arguing that there is not enough momentum in the regular AGB winds to explain the high momenta outflows observed in PPNe, so basically he was questioning the assumption of the model (echoed by another participant, Alcolea). He says therefore one needs a jet. Also appeals to the precession seen in some sources to argue for jets. Says that jets have been seen in post-AGB objects (refers to Van Winckel). Interestingly, Noam thinks that jets can emerge/break out before or after the CE phase, but are unable to do so during the CE phase.
• In the discussion it was also mentioned by Paul Ricker (echoed by Morgan MacLeod) that in the Heidelburg group sims that utilize recombination energy, they compute that the energy is used in regions where tau>1, but maybe the radiative diffusion time is still small enough that the energy escapes to the surface, so maybe it could not be used so easily. They didn't seem to have an answer for that.
• In the discussion, David Jones commented that post-CE PN CSs seem to be tidally locked, at least there is no evidence for asynchronous rotation. Again, perhaps something to think about.
• In the discussion, David Jones also mentioned that mass is still missing in PNe. It is not all contained in the equatorial disk, so where is the rest? Alocolea says velocity profile does not fit story that equatorial material is left over CE ejecta, and he sees the velocity turning around (I guess this would imply fallback).
• J. Jencson: SPRITES: rapid dust formation and dust obscures optical counterpart. I think this is another reason to have dust in our CE simulations.
• N. Blogorodnova: From her talk I wonder if the secondary peak/plateau in LRNe/ILOTs caused by a second unbinding phase+merger. This does not seem to be the popular idea people have. They found for M31LRN 2015 that temperature increases with time at late times and that the luminosity agrees with gravitational contraction at fixed temperature. Anyway, her talk is mainly about observations of that source, and may be worth watching.

(I'm on leave next week so I won't be at this meeting!)

Objectives

• Debugging (now moved on to sputtering as well)
• Refine dust routines

Progress:

• HPC Proposal: I need to write one this month so progress on other topics might be slow towards the end of the month.
• MHD Clouds Crushing Simulations: Did a ton of simulation for our next paper to show the effect of different magnet field orientations on the Cloud Crushing Setup. I will make another blog post with plots and videos at some point but my computer decided to transition to laptop heaven and while I'm waiting on a new one I can't properly use visit.
• Debugging: Made progress here and have also started looking at the sputtering but I don't trust it yet and want to invest more time comparing my results with the dust post-processing results. Currently, simulations look a bit "grainy" which seems off considering that the gas looks smooth.

Up Next:

• Haven't forgotten about the ​equations for the dust grain size distributions! I will add them once I've checked something and made sure I'm actually implementing what I want. Looks a bit strange at the moment.
• Continue debugging of sputtering + check ion trapping & gas feedback is implemented correctly.
• Setting up Sputtering comparison with the dust post-processing code.
• I'm aiming to do production runs for drag and sputtering in August and while that's going on I'll add the rest of the grain-grain collisions code.

Goal: Figure out how to make the probe velocity and range normally distributed within our FORTRAN model.
Summary of Progress: ​Click here to see the PDF which summarizes my progress so far and my next steps.
Video Of Current Model Output (Colored by Technology, Pink=Unsettled): ​http://www.pas.rochester.edu/~esavitch/fermiProject/results2.ogv

To familiarise myself with AstroBear and various parameters, I have been running a problem which involves a collision between two jets

Trial 0: ran the problem as provided

Trial 1: Changed density of top jet from 6e16 to 3e16

Trial 2: Same as Trial 0, but increased density of ambient medium to 1e17 Took several attempts to get Visit to cooperate

Trial 3: Combine changes of both Trial 1 and Trial 2

Trial 4: Repeat Trial 3 with 160 frames, final time changed from 0.2 to 0.4

Trial 5: Same as Trial 4, but use ambient density 4e16 (i.e. between the densities of the jets). I accidentally overwrote the chombo files for this run so I will have to rerun it if I want anything other than this gif

Trial 6: Reran trial 2 at 4 levels of refinement. Since I'm running in debug this limited me to 22 frames (which I have since lost).