Discussion with Marco

General Overview
Questions or Discussion.

6/11/2020- (with Marco by emails)
- To summarize what we discussed so far, to include C-shell burning in massive stars, I evaluated at radius 4.5 solar mass (suggested by Umberto ~5, at least >4) at cycle 9000 (suggested by Umberto). For He-core only, I used cycle 3500.

12/1/2020- (with Marco & Umberto by emails)
- To evaluate s-process in massive stars (25M,e.g.), I need to include C shell burning too (so set the mass coordinate and cycle by finding the location in KH diagram)

- My past calculations all used default 22Ne(a,g), though each time I changed vital.F90 setting. It's because you have to set to "T (true)" in ppn_physics.input as well! (1/4/2021)

How to compare massive stars simulation results with observations.
- Pick up typical elements from massive stars, e.g., Sr, Zr (weak s-process massive stars), 98% of whose elements come from massive stars

- Starting with 0.01Z – alpha elements 0.06%, (Canfar) massive star, check if it reproduces solar system composition or GCE (Galactic Chemical Evolution), or last generation stars (typical composition)

- Ge (weak s massive stars; 70 s-only) 70Ge/Ge72 → (73Ge(n,g) nTOF) impact, this may be a good candidate.

How to define final abundance of massive stars (pre supernova)

- C-shell (check kippenhaan diagram (recommended by Umberto) or just check like Marco does in his papers)

- To check C-shell He burning is achieved, see C-composition

- Kippenhanan diagram can be drawn by (NuGridPy) mesa.py → kippenhahn function (this should be ok (read star.log from Mesa outputs), kip_cont, kippenhaan CO functions are for some other purposes.

- In Umberto's example output (probably 10-15 solar mass), 4300 – 4400 cycle, Mass = 1.25-2 mass (check middle of the zone) are the positions to call as final abundance.

- You can draw kiiepnhaan diagram like below,

import mesa as ms ls st1=ms.star_log('.') <--- find star_log.file in the current directory. st1.kippenhahn? st1.kippenhahn(1,'logtimerev') plt.gca.invert_yaxis st1.kippenhahn(1,'logtimerev') plt.gca.invert_xaxis st1.kippenhahn(1,'model')

94Zr(n,g), 95Zr(n,g)
- PPN or MPPNP whichever is ok to check the sensitivity to final abundances.

- Networksetup.txt → change rate from 1 to XX

- set ININET = 3 in ppn_physics (this makes PPN/MPPNP read reaction rate from networksetup.txt)

9/1 - 9/7/2019 (NuGrid Meeting, Budapest)
- To change reaction rates by factors, change rate_factor in NuPPN/physics/source/physics_knob.F90 (Ashly).

- OZone is single zone trajectory (Adria).

- PPN doesn't handle convection, but MPPNP does. Running MPPPNP is almost same as running MESA, so no trajectory input is needed. MPPNP needs to be run on cluster computer for efficient computation.

- How to avoid reaching MAX_SUBSTEP and calculation stopping?

- Why some trajectory files (in example codes) seem like time-reversal? (temperature and density decreases with time, e.g., M25_ccsn) --> because the time is delta t (time interval).

- Why some trajectory files (in example codes) contain same time but different temp and rho (e.g., M25_weak_s/center, mixed)? --> because the time is delta t.

8/21/2019 (read a paper)
- I like Marco's this paper (about 12C+12C in massive stars for s-process; hard to read, but important and related to my interest].

7/17/2019
- If I need to make trajectory.input from MESA. How? (which output variables in MESA?; especially case of shell burning)

--> Not needed. Already there exist many calculations using different patters of metallicity, solar mass, initial abundances on http://www.canfar.net/en. For example, check https://www.canfar.net/storage/list/nugrid/data/set1ext/set1.2. or https://www.canfar.net/storage/list//nugrid/data/set1ext/set1.2/see_wind/M2.00Z2.0e-2/. Download h5.out. If you want to know MESA input files, check inlist and reaction network directory.

- Is it normal that Carbon core produces neutron more than He shell (for s-process). If so, why no s-process occurs in the Carbon core?

Depends on reaction network that I set. If no neutron poisons are set well (MESA is not good at it due to limited network and isotopes), that's very possible. Marco suggested to read this paper

- Why 22Ne(a,n) should be the neutron source? Other reactions such as 18O(a,n) cycle back or be neutron poison?

Because of possible neutron recycling. For example, 12C(n,g) --> 13C(a,n) --> net neutron is 0. Likewise, 16O(n,g)->17O(a,n) and 21Ne(n,g) --> 22Ne(a,n). 22Ne (and 13C) are special because there exist many already.

- How to install MPPNP? (how to install SE library and openmpi?)

Not discussed this time.

- abu_chart.py error (currently I need to hard-code in data_plot.py)

Not discussed this time.

- What is tppnp?

MPPNP specialized for extracting trajectory.

- How to change nuclear reaction rate? (NuPPN/physics/NPDATA)

Change NuPPN/physics/source/vital.F90 (remember to make in the running directory), ppn_physics.input Check Marco's paper too.

6/30/2019
- How to install NuPPN