# constants

Fortran module: `constants`

## Constants (Read-Only)

Fortran PARAMETER constants (compile-time values):

| Constant | Type | Value |
|----------|------|-------|
| `amu` | `<class 'numpy.ndarray'>` | `1.66053892e-24` |
| `au` | `<class 'numpy.ndarray'>` | `206300.0` |
| `aunit` | `<class 'numpy.ndarray'>` | `14959780000000.0` |
| `c` | `<class 'numpy.ndarray'>` | `29979245800.0` |
| `chem_init_error` | `<class 'numpy.ndarray'>` | `-3` |
| `conservation_error` | `<class 'numpy.ndarray'>` | `-16` |
| `coolant_config_error` | `<class 'numpy.ndarray'>` | `-14` |
| `coolant_data_error` | `<class 'numpy.ndarray'>` | `-10` |
| `coolant_file_error` | `<class 'numpy.ndarray'>` | `-9` |
| `coolant_freq_tol_error` | `<class 'numpy.ndarray'>` | `-11` |
| `coolant_pop_tol_error` | `<class 'numpy.ndarray'>` | `-12` |
| `coolant_solver_error` | `<class 'numpy.ndarray'>` | `-13` |
| `dp` | `<class 'numpy.ndarray'>` | `8` |
| `ev` | `<class 'numpy.ndarray'>` | `1.60217646e-12` |
| `grav_g` | `<class 'numpy.ndarray'>` | `6.674e-08` |
| `habing_to_draine` | `<class 'numpy.ndarray'>` | `0.5882352590560913` |
| `hp` | `<class 'numpy.ndarray'>` | `6.62606896e-27` |
| `hp_si` | `<class 'numpy.ndarray'>` | `6.62607015e-34` |
| `int_too_many_fails_error` | `<class 'numpy.ndarray'>` | `-5` |
| `int_unrecoverable_error` | `<class 'numpy.ndarray'>` | `-4` |
| `k_boltz` | `<class 'numpy.ndarray'>` | `1.3806504e-16` |
| `k_boltz_si` | `<class 'numpy.ndarray'>` | `1.38e-23` |
| `kcal_to_joule` | `<class 'numpy.ndarray'>` | `4184.0` |
| `km` | `<class 'numpy.ndarray'>` | `100000.0` |
| `lsun` | `<class 'numpy.ndarray'>` | `3.828e+33` |
| `mh` | `<class 'numpy.ndarray'>` | `1.67262164e-24` |
| `n_avogadro` | `<class 'numpy.ndarray'>` | `6.022140857e+23` |
| `negative_abundance_error` | `<class 'numpy.ndarray'>` | `-15` |
| `not_enough_timepoints_error` | `<class 'numpy.ndarray'>` | `-6` |
| `parameter_read_error` | `<class 'numpy.ndarray'>` | `-1` |
| `pc` | `<class 'numpy.ndarray'>` | `3.086e+18` |
| `physics_init_error` | `<class 'numpy.ndarray'>` | `-2` |
| `physics_update_error` | `<class 'numpy.ndarray'>` | `-7` |
| `pi` | `<class 'numpy.ndarray'>` | `3.1415927410125732` |
| `reac_not_present` | `<class 'numpy.ndarray'>` | `99999` |
| `reduced_planck` | `<class 'numpy.ndarray'>` | `1.054571628e-27` |
| `sb_const` | `<class 'numpy.ndarray'>` | `5.6704e-05` |
| `seconds_per_year` | `<class 'numpy.ndarray'>` | `31600000.0` |
| `solver_stats_overflow_error` | `<class 'numpy.ndarray'>` | `-8` |
| `t_cmb` | `<class 'numpy.ndarray'>` | `2.7300000190734863` |
| `uisrf` | `<class 'numpy.ndarray'>` | `8.64e-13` |
| `uisrf_uv` | `<class 'numpy.ndarray'>` | `5.2899999376625206e-14` |
| `zero_inner_radius_error` | `<class 'numpy.ndarray'>` | `-17` |

## Runtime Access

Access `constants` parameters at runtime using `uclchem.advanced.GeneralSettings()`.
See [Accessing Fortran Parameters](index.html#accessing-fortran-parameters-at-runtime) on the main Fortran API page for examples.