## How to Interpret your MESA-Web Calculation

Once your MESA-Web calculation has finished, you will have a directory which contains the data from your stellar model. We describe below how to interpret this data and also recommend the user visit the Tools & Utilities section to helpful resources to begin plotting your data.

### Movies

MESA-Web calculations output mp4 videos constructed using PGSTAR, the live plotting software allowing a user to dynamically plot MESA output variables. The plots include: an abundance profile, Kippenhahn diagram, HR Diagram, Rotational profile, and T-Rho-P profile panels.Diagrams are created at every fifth timestep and a mp4 is rendered using the snapshots the end of your MESA-Web calculation to provide a visual history of the overall evolutionary properties of your model. An example of a 15M star is shown below:

### History Output

MESA-Web calculations contain a 'trimmed_history.data' file that contains items of interest about your stellar model at each timestep. The history output provides general information about the entire star at a particular timestep and are described below:

Column | 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_{☉}) |
Mass of the star in terms of Solar Mass |

4 | log L (L_{☉}) |
Luminosity of the star in terms of log10 Solar Luminosity |

5 | log R (R_{☉}) |
Radius of the star in terms of log10 Solar Radii |

6 | log T_{eff} (K) |
Log10 effective temperature of the star |

7 | log T_{c} (K) |
Log10 temperature at the center of the star |

8 | log ρ_{c} (g cm^{-3}) |
Log10 density at the center of the star |

9 | log P_{c} (dyn cm^{-2}) |
Log10 pressure at the center of the star |

10 | η_{c}/k_{B}T |
The electron chemical potential |

11 | X(^{1}H) |
Hydrogen mass fraction at the center of the star |

12 | X(^{4}He) |
Helium mass fraction at the center of the star |

13 | X(^{12}C) |
Carbon 12 mass fraction at the center of the star |

14 | X(^{14}N) |
Nitrogen 14 mass fraction at the center of the star |

15 | X(^{16}O) |
Oxygen 16 mass fraction at the center of the star |

16 | X(^{18}O) |
Oxygen 18 mass fraction at the center of the star |

17 | X(^{22}Ne) |
Neon 22 mass fraction at the center of the star |

18 | τ_{dyn} (s) |
Dynamical timescale of the star |

19 | τ_{kh} (s) |
Kelvin-Helmholtz timescale of the star |

20 | τ_{nuc} (s) |
Nuclear timescale of the star |

21 | log L_{pp} (L_{☉}) |
Log 10 luminosity due to all pp chain reactions |

22 | log L_{CNO} (L_{☉}) |
Log 10 luminosity due to CNO cycle |

23 | log L_{3α} (L_{☉}) |
Log 10 luminosity due to the triple alpha process |

24 | log L_{Z} (L_{☉}) |
Log 10 luminosity due to all nuclear burning excluding H and He |

25 | log L_{ν} (L_{☉}) |
Log 10 luminosity emitted by neutrinos (thermal and nuclear) |

26 | M_{He} (M_{☉}) |
Amount of mass enclosed in outermost region where the Helium 4 mass fraction is greater than 0.01 |

27 | M_{C} (M_{☉}) |
Amount of mass enclosed in outermost region where the Carbon 12 mass fraction is greater than 0.01 |

28 | M_{O} (M_{☉}) |
Amount of mass enclosed in outermost region where the Oxygen 16 mass fraction is greater than 0.01 |

29 | R_{He} (R_{☉}) |
Radius of outermost region where the Helium 4 mass fraction is greater than 0.01 |

30 | R_{C} (R_{☉}) |
Radius of outermost region where the Carbon 12 mass fraction is greater than 0.01 |

31 | R_{O} (R_{☉}) |
Radius of outermost region where the Oxygen 16 mass fraction is greater than 0.01 |

32 | (Ω_{ZAMS}/Ω_{crit})_{i,surf} |
Surface Average angular frequency divided by the Keplerian critical angular frequency at ZAMS |

33 | log J_{total} (g cm^{2}s^{-1}) |
Log 10 total angular momentum of the star at a particular model |

34 | Ω_{surf} (rad s^{-1}) |
Surface Average angular frequency |

35 | v_{rot,surf} (km s^{-1}) |
Surface Average Rotational Velocity |

36 | dM/dt (M_{☉} yr^{-1}) |
Mass Loss Rate |

### Profile Output

MESA-Web calculations contain multiple 'profile$N.dat' files, where $N is the N'th profile of your calculation. MESA profile files contain information about each zone in your stellar model at a discrete timestep. A list explaining which profile corresponds to which timestep number can be found in the 'profiles.index' file from your calculation. The profile output provides general information about the entire star at a particular model number and are described below:

Column | 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 | log ρ (g cm^{-3}) |
Log 10 density at center of zone |

6 | log T (K) | Log 10 temperature at center of zone |

7 | E_{int} (erg g^{-1}) |
Internal energy |

8 | S/N_{A}k_{B} |
Specific entropy |

9 | C_{p} (erg g^{-1}K^{-1}) |
Specific heat capacity at constant total pressure |

10 | Γ_{1} (∂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 | n_{e-} (N_{e-} cm^{-3}) |
Mean number of free electrons per nucleon |

14 | P_{gas} (dyn cm^{-2}) |
Gas pressure at center of zone (electrons and ions) |

15 | P_{rad} (dyn cm^{-2}) |
Radiation pressure at center of zone |

16 | ∇_{rad} (∂lnT/∂lnρ)_{S} |
Radiative temperature gradient |

17 | ∇_{T} (K g^{-1}) |
Temperature gradient |

18 | v_{conv} (cm s^{-1}) |
Convection velocity |

19 | κ (cm^{2} g^{-1}) |
Opacity measured at the center of zone |

20 | ε_{nuc} (erg g^{-1} s^{-1}) |
Energy generation rate from all nuclear reactions excluding those from neutrino reactions |

21 | ε_{pp} (erg g^{-1} s^{-1}) |
Energy generation rate from pp chain reactions |

22 | ε_{CNO} (erg g^{-1} s^{-1}) |
Energy generation rate from CNO cycle |

23 | ε_{3α} (erg g^{-1} s^{-1}) |
Energy generation rate from triple alpha process |

24 | ε_{ν} (erg g^{-1} s^{-1}) |
Energy generation rate of neutrinos from all reactions |

25 | ε_{cool} (erg g^{-1} s^{-1}) |
Non-nuclear-reaction neutrino losses |

26 | ε_{grav} (erg g^{-1} s^{-1}) |
Gravitational heating rate |

27 | X(^{1}H) |
Hydrogen mass fraction |

28 | X(^{3}He) |
Helium 3 mass fraction |

29 | X(^{4}He) |
Helium 4 mass fraction |

30 | X(^{12}C) |
Carbon 12 mass fraction |

31 | X(^{14}N) |
Nitrogen 14 mass fraction |

32 | X(^{16}O) |
Oxygen 16 mass fraction |

33 | X(^{18}O) |
Oxygen 18 mass fraction |

34 | X(^{22}Ne) |
Neon 22 mass fraction |

35 | η | Electron Degeneracy Parameter |

36 | log ω (rad s^{-1}) |
Log 10 specific angular frequency |

37 | v_{rot} (km s^{-1}) |
Rotational velocity at cell boundary |

38 | j (g cm^{2} s^{-1}) |
Specific angular momentum |

39 | log B_{r} (Gauss) |
Log 10 radial magnetic field |

40 | log B_{φ} (Gauss) |
Log 10 azimuthal magnetic field |

41 | log D_{conv} (cm^{2} s^{-1}) |
Log 10 D_{mix} for regions where mix_type = convective_mixing |