# MESA-Web Input

This page describes the input parameters appearing on the submission page. For more detailed information about these parameters, consult the full MESA documentation.

- Initial Properties
- Nuclear Reactions
- Mixing
- Winds
- Numerical Resolution
- Custom Stopping Condition
- General

## Initial Properties

- Mass
- Initial mass of the star, in solar masses. Must lie in the range [0.1,100].
- Metallicity
- Initial uniform metallicity of the stellar material, expressed as the mass fraction of metals.
- Rotation Rate (Ω
_{ZAMS}/Ω_{crit})_{i} - Initial uniform rotation rate of the star, expressed as the ratio between the rotational angular velocity and the critical angular velocity. Must lie in the range [0.0, 1.0].

## Nuclear Reactions

- Network
- Name of the nuclear reaction network. See
*MESA-Web*Nuclear Reaction Networks for further details. - Custom Nuclear Reaction Rate
- Nuclear reaction to customize, expressed in compact notation.
- Upload Rate
- Name of upload file containing reaction rate data for customized reaction. This file must have the following format:
- Zero or more lines beginning with a hash (#) mark; these are treated as comments and ignored.
- Exactly one line consisting of a single integer, giving the number of subsequent T8/rate lines.
- One or more lines containing a space-separated T8/rate pair, where T8 is the temperature in units of 10
^{8}kelvin, and rate is the reaction rate in units of per second.

Interpolation is used to evaluate the rate between the tabulated values.

## Mixing

### Convection

- Mixing Length Alpha (α
_{MLT}) - Mixing length, in units of the local pressure scale height. Must be greater than or equal to zero.
- Mixing Length Theory Prescription
- Implementation of mixing-length theory for convective energy transport; one of:
- none
- Disable convection, forcing energy transport to be purely radiative
- Cox
- Prescription described by Chapter 14 of Cox & Giuli (1968)
- MLT1
- Prescription described by Böhm-Vitense (1958)
- MLT2
- Prescription described by Böhm & Cassinelli (1971)
- Mihalas
- Prescription described by Mihalas (1978)
- Henyey
- Prescription described by Henyey, Vardya, and Bodenheimer (1965)

- Boundary Mixing
- Prescription for placement and mixing processes at the boundaries of convection zones. Predictive mixing is described in Paxton et al. (2018), and convective premixing (CPM) in Paxton et al. (2019)

### Convective Overshoot

- Overshoot
*f* - Overshoot scale length parameter, as defined in eqn. 2 of Paxton et al. (2011). Must be greater than or equal to zero.
- Overshoot
*f*_{0} - Overshoot boundary offset parameter, as explained below eqn. 2 of Moravveji et al. (2016). Must be greater than or equal to zero.

### Semi-Convection

- Semi-Convection Alpha (α
_{semi}) - Semi-convection efficiency parameter, as defined in eqn. 12 of Paxton et al. (2013). Must be greater than or equal to zero.

### Thermohaline

- Thermohaline Alpha (α
_{th}) - Thermohaline efficiency parameter, as defined in eqn. 14 of Paxton et al. (2013). Must be greater than or equal to zero.
- Thermohaline Mixing Prescription
- Implementation of thermohaline mixing; one of:
- Kippenhahn
- Prescription described by Kippenhahn et al. (1980)
- Traxler_Garaud_Stellmach_11
- Prescription described by Traxler et al. (2013)
- Brown_Garaud_Stellmach_13
- Prescription described by Brown et al. (2013)

## Winds

- Red Giant Branch Wind Prescription
- Implementation of wind mass loss on the red giant branch; one of:
- Reimers
- Prescription described by Reimers (1975)
- Blocker
- Prescription described by Blöcker (1995)
- Kudritzki
- Prescription described by Kudritzki et al. (1989)
- Nieuwenhuijzen
- Prescription described by Nieuwenhuijzen & de Jager (1990)
- Vink
- Prescription described by Vink et al. (2001)
- Grafener
- Prescription described by Gräfener & Hamann (2008)
- Dutch
- Prescription described by Glebbeek et al. (2009)

- RGB Wind Scaling Factor
- Scaling factor for wind mass loss rate on the red giant branch. Must be greater than or equal to zero.
- Asymptotic Giant Branch Wind Prescription
- Implementation of wind mass loss on the red giant branch; same options as Red Giant Branch Wind Prescription.
- AGB Wind Scaling Factor
- Scaling factor for wind mass loss rate on the asymptotic giant branch. Must be greater than or equal to zero.

## Numerical Resolution

### Spatial (Mass) Resolution - Global

- Mesh Delta Coefficient
- Spatial grid resolution coefficient. A larger value increases the maximum allowed spacing between grid points, and so decreases the total number of grid points; vice-versa for a smaller value. Doubling the coefficient will roughly (but not exactly) half the number of grid points.

### Temporal (Time) Resolution - Global

- Variance Control Target
- Target value for relative model variation between one timestep and the next. A larger value allows for larger timesteps; vice-versa for a smaller value.
- dX_nuc_drop_min_X_limit
- Minimum hydrogen mass fraction at which drops in hydrogen abundance, due to nuclear burning, are monitored when choosing timesteps.

### Temporal (Time) Resolution - Hydrogen

- delta_lg_XH_cntr_min
- Logarithm of minimum central hydrogen abundance at which delta_lg_XH_cntr_limit and delta_lg_XH_cntr_hard_limit apply.
- delta_lg_XH_cntr_max
- Logarithm of maximum central hydrogen abundance at which delta_lg_XH_cntr_limit and delta_lg_XH_cntr_hard_limit apply.
- delta_lg_XH_cntr_limit
- Limit for change in logarithm of central hydrogen abundance, across a single timestep; timesteps are reduced to attempt to honor this limit.
- delta_lg_XH_cntr_hard_limit
- Hard limit for change in logarithm of central hydrogen abundance, across a single timestep; timesteps are reduced to guarantee this limit is honored.

## Custom Stopping Condition

- Quantity
- Quantity to monitor to decide when to stop the calculation.
- Value
- Corresponding value to monitor.

## General

- Detailed Profile Output Frequency
- Number of timesteps between consecutive profile (detailed structure) files.
- MESA Release
- Release (version) of the MESA code to use for calculations. Leave as the default value unless trying to reproduce legacy calculations.
- Email Address
- Email address to send Zip archive to, upon job completion (either through the stopping condition being met, or the 2-hour time limit being reached; whichever comes first). See the
*MESA-Web*Output page for details of the contents of the archive.

Updated 2024-03-08 06:26:59