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:
- (upper-left): abundance profiles, plotting the mass fractions of selected nuclides as a function of mass coordinate within the star;
- (upper-mid): a Kippenhahn diagram;
- (lower-left): a Hertzsprung-Russell Diagram;
- (lower-mid): a density-temperature plot;
- (right): thermodynamic state profiles, plotting the total pressure (upper), density (mid), and temperature (lower) as a function of mass coordinate within the star.
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 L3α (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 | (ΩZAMS/Ωcrit)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 |
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 | ε3α (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.