Output from MESA-Web

Once a MESA-Web calculation completes, you will receive an email containing a link to a Zip archive. Download and unpack this archive to obtain a 'job' directory (folder) with a name of the form MESA-Web_job_JJJJ, where JJJJ is a sequence of digits known as the 'run id'. The job directory contains variety of files produced by MESA-Web. The following sections describe these output files, and explain how to read them into Python.

Movie Output

The movie file, MESA-Web_job_JJJJ.mp4, contains an MP4-format movie constructed using PGSTAR, the live plotting software allowing a user to dynamically plot MESA output variables. The data shown in the movie are divided into a number of panels:

Each frame of the movie is based on data from every fifth timestep of MESA. An example of a movie for a 1M star, evolving from the pre-main sequence phase through to a cooling white dwarf, is shown here:

History Output

The history file, named trimmed_history.data, provides general information about the entire stellar model as a function of time. The file consists of a few header lines giving global data, followed by a sequence of rows correspond to individual timesteps. The columns of each row contain the following data:

Column Number Datum Description
1 Model Number Number of model from the start of the calculation
2 Age (yr) Elapsed simulated time since the start of the calculation
3 Mass (M) Total mass of the star
4 log10 L (L) Luminosity of the star at the outermost cell
5 log10 R (R) Radius of the star at the outermost cell
6 log10 Teff (K) Log10 effective temperature of the star
7 log10 Tc (K) Log10 temperature at the center of the star
8 log10 ρc (g cm-3) Log10 density at the center of the star
9 log10 Pc (dyn cm-2) Log10 pressure at the center of the star
10 Xc(1H) Hydrogen 1 mass fraction at the center of the star
11 Xc(3He) Helium 3 mass fraction at the center of the star
12 Xc(4He) Helium mass fraction at the center of the star
13 Xc(12C) Carbon 12 mass fraction at the center of the star
14 Xc(14N) Nitrogen 14 mass fraction at the center of the star
15 Xc(16O) Oxygen 16 mass fraction at the center of the star
16 Xc(20Ne) Neon 20 mass fraction at the center of the star
17 Xc(24Mg) Magnesium 24 mass fraction at the center of the star
18 Xc(28Si) Silicon 28 mass fraction at the center of the star
19 Xc(32S) Sulfur 32 mass fraction at the center of the star
20 Xc(36Ar) Argon 36 mass fraction at the center of the star
21 Xc(40Ca) Calcium 40 mass fraction at the center of the star
22 Xc(44Ti) Titanium 44 mass fraction at the center of the star
23 Xc(48Cr) Chromium 48 mass fraction at the center of the star
24 Xc(52Fe) Iron 52 mass fraction at the center of the star
25 Xc(54Fe) Iron 54 mass fraction at the center of the star
26 Xc(56Fe) Iron 56 mass fraction at the center of the star
27 Xc(56Ni) Nickel 56 mass fraction at the center of the star
28 ηc/kBT The electron chemical potential at the center of the star
29 Ye,c The ratio of electrons to baryons at the center of the star
30 Sc/(kB baryon) The entropy at the center of the star
31 ξm=2.5 M Compactness parameter
32 τdyn (s) Dynamical timescale of the star
33 τkh (s) Kelvin-Helmholtz timescale of the star
34 τnuc (s) Nuclear timescale of the star
35 log10 Lpp (L) Log10 luminosity due to all pp chain reactions
36 log10 LCNO (L) Log10 luminosity due to CNO cycle
37 log10 L (L) Log10 luminosity due to the triple alpha process
38 log10 LH (L) Log10 luminosity due to all H nuclear burning
39 log10 LHe (L) Log10 luminosity due to all He nuclear burning
40 log10 LZ (L) Log10 luminosity due to all nuclear burning excluding H and He
41 log10 Lν (L) Log10 luminosity emitted by neutrinos (thermal and nuclear)
42 MHe (M) Amount of mass enclosed in outermost region where the Helium 4 mass fraction is greater than 0.01
43 MC (M) Amount of mass enclosed in outermost region where the Carbon 12 mass fraction is greater than 0.01
44 MO (M) Amount of mass enclosed in outermost region where the Oxygen 16 mass fraction is greater than 0.01
45 MSi (M) Amount of mass enclosed in outermost region where the Silicon 28 mass fraction is greater than 0.01
46 MFe (M) Amount of mass enclosed in outermost region where the Iron 56 mass fraction is greater than 0.01
47 RHe (R) Radius of outermost region where the Helium 4 mass fraction is greater than 0.01
48 RC (R) Radius of outermost region where the Carbon 12 mass fraction is greater than 0.01
49 RO (R) Radius of outermost region where the Oxygen 16 mass fraction is greater than 0.01
50 RSi (R) Radius of outermost region where the Silicon 28 mass fraction is greater than 0.01
51 RFe (R) Radius of outermost region where the Iron 56 mass fraction is greater than 0.01
52 |vmax| (cm s-1) Absolute value of maximum velocity of the star
53 ZAMScrit)i,surf Surface Average angular frequency divided by the Keplerian critical angular frequency at ZAMS
54 log10 Jtotal (g cm2s-1) Log10 total angular momentum of the star at a particular model
55 Ωsurf (rad s-1) Surface Average angular frequency
56 vrot,surf (km s-1) Surface Average Rotational Velocity
57 dM/dt (M yr-1) Mass Loss Rate
58 I (cm2 g) Moment of inertia

Profile Output

The profile files, named profileN.dat (where N is an integer counting up from 1), contain information about the internal structure of the stellar model at a single timestep. The mapping between profile number N and timestep is provided in the file named profiles.index. A profile file consists of a few header lines giving global data, followed by a sequence of rows correspond to individual interior zones (ordered from the outermost zone to the innermost). The columns of each row contain the following data:

Column Number Datum Description
1 m (M) Mass coordinate of outer boundary of zone
2 r (R) Radius at outer boundary of zone
3 L (L) Luminosity at outer boundary of zone
4 P (dyn cm-2) Total pressure at center of zone (radiation + gas)
5 log10 ρ (g cm-3) Log10 density at center of zone
6 log10 T (K) Log10 temperature at center of zone
7 Eint (erg g-1) Internal energy
8 S/NAkB Specific entropy
9 Cp (erg g-1K-1) Specific heat capacity at constant total pressure
10 Γ1 (∂lnP/∂lnρ)S Gamma 1 at constant entropy
11 ad Adiabatic temperature gradient at constant entropy
12 μ Mean molecular weight per gas particle (ions + free electrons)
13 ne- (Ne- cm-3) Mean number of free electrons per nucleon
14 Ye Specific ratio of electrons to baryons
15 Pgas (dyn cm-2) Gas pressure at center of zone (electrons and ions)
16 Prad (dyn cm-2) Radiation pressure at center of zone
17 rad (∂lnT/∂lnρ)S Radiative temperature gradient
18 T Temperature gradient
19 v (cm s-1) Velocity at outer boundary of zone
20 vconv (cm s-1) Convection velocity
21 κ (cm2 g-1) Opacity measured at the center of zone
22 εnuc (erg g-1 s-1) Energy generation rate from all nuclear reactions excluding those from neutrino reactions
23 εpp (erg g-1 s-1) Energy generation rate from pp chain reactions
24 εCNO (erg g-1 s-1) Energy generation rate from CNO cycle
25 ε (erg g-1 s-1) Energy generation rate from triple alpha process
26 εν (erg g-1 s-1) Energy generation rate of neutrinos from all reactions
27 εcool (erg g-1 s-1) Non-nuclear-reaction neutrino losses
28 εgrav (erg g-1 s-1) Gravitational heating rate
29 X(1H) Hydrogen mass fraction
30 X(3He) Helium 3 mass fraction
31 X(4He) Helium 4 mass fraction
32 X(12C) Carbon 12 mass fraction
33 X(14N) Nitrogen 14 mass fraction
34 X(16O) Oxygen 16 mass fraction
35 X(20Ne) Neon 20 mass fraction
36 X(24Mg) Magnesium 24 mass fraction
37 X(28Si) Silicon 28 mass fraction
38 X(32S) Sulfur 32 mass fraction
39 X(36Ar) Argon 36 mass fraction
40 X(40Ca) Calcium 40 mass fraction
41 X(44Ti) Titanium 44 mass fraction
42 X(48Cr) Chromium 48 mass fraction
43 X(52Fe) Iron 52 mass fraction
44 X(54Fe) Iron 54 mass fraction
45 X(56Fe) Iron 56 mass fraction
46 X(56Ni) Nickel 56 mass fraction
47 η Electron Degeneracy Parameter
48 log10 ω (rad s-1) Log10 specific angular frequency
49 vrot (km s-1) Rotational velocity at cell boundary
50 j (g cm2 s-1) Specific angular momentum
51 log10 Br (Gauss) Log10 radial magnetic field
52 log10 Bφ (Gauss) Log10 azimuthal magnetic field
53 log10 Dconv (cm2 s-1) Log10 Dmix for regions where mix_type = convective_mixing
54 log10 Dsemi (cm2 s-1) Log10 Dmix for regions where mix_type = semiconvective_mixing
55 log10 Dovr (cm2 s-1) Log10 Dmix for regions where mix_type = overshoot_mixing
56 log10 Dthrm (cm2 s-1) Log10 Dmix for regions where mix_type = thermohaline_mixing

Python Analysis

To facilitate reading history and profile files into Python, we've created a module called mesa_web.py. Download the module (by clicking on the link), and place it either in your working directory or somewhere in your Python path. This module provides three functions:

read_history()
read a history file.
read_profile()
read a profile file.
find_read_profile()
find a profile file using the profiles.index mapping file, and then read it.

All three functions return either a Python dict, or an astropy.table.Table object. See the help documentation [e.g., help(read_history)] for details about function arguments.


Updated 2023-12-11 15:34:21