This subpackage defines several constants that are used in analyzing gravity,
topography, and magnetic field data of the terrestrial planets. Each object is
an astropy `Constant`

that possesses the attributes name, value, unit,
uncertainty, and reference.

## Fundamental constants

Constant | Description |
---|---|

`G` |
Gravitational Constant |

`mu0` |
Magnetic constant |

## Mercury

Constant | Description |
---|---|

`r_mercury` |
Average radius of Mercury |

`gm_mercury` |
Gravitational constant times the mass of the Mercury |

`mass_mercury` |
Mass of Mercury |

`omega_orbit_mercury` |
Angular rotation rate of Mercury about the Sun |

`omega_mercury` |
Angular rotation rate of Mercury |

`density_mercury` |
Average density of Mercury |

`g0_mercury` |
Gravitational acceleration at `r_mercury` , not including rotation |

## Venus

Constant | Description |
---|---|

`r_venus` |
Average radius of Venus |

`gm_venus` |
Gravitational constant times the mass of the Venus |

`mass_venus` |
Mass of Venus |

`omega_venus` |
Angular rotation rate of Venus |

`density_venus` |
Average density of Venus |

`g0_venus` |
Gravitational acceleration at `r_venus` , not including rotation |

## Earth

Constant | Description |
---|---|

`gm_egm2008` |
Gravitational constant times the mass of Earth from the EGM2008 model |

`mass_egm2008` |
The mass of Earth from the EGM2008 model |

`a_wgs84` |
The semi-major axis of the WGS84 ellipsoid |

`b_wgs84` |
The semi-minor axis of the WGS84 ellipsoid |

`r3_wgs84` |
The radius of a sphere of Earth’s volume |

`f_wgs84` |
The flattening of the WGS84 ellipsoid |

`gm_wgs84` |
The adopted GM of the WGS84 model, which includes the atmosphere |

`mass_wgs84` |
The mass of Earth from the WGS84 model, which includes the atmosphere |

`gma_wgs84` |
The GM of the atmosphere adopted by the WGS84 model |

`omega_wgs84` |
The adopted angular rotation rate of the Earth of the WGS84 model |

`u0_wgs84` |
The theoretical normal potential associated with the WGS84 model |

## The Moon

Constant | Description |
---|---|

`r_moon` |
Mean radius of the Moon |

`gm_moon` |
Gravitational constant times the mass of the Moon |

`mass_moon` |
Mass of the Moon |

`density_moon` |
Average density of the Moon |

`a_orbit_moon` |
Semi-major axis of the lunar orbit |

`g0_moon` |
Mean gravitational acceleration of the Moon at the mean surface radius (`r_moon` ), not including rotation |

`omega_moon` |
Angular rotation rate of the Moon |

`i_solid_moon` |
Average moment of inertial of the solid portion of the Moon |

`gamma_moon` |
Libration parameter of the Moon, (B-A)/C |

`beta_moon` |
Libration parameter of the Moon, (C-A)/B |

## Mars

Constant | Description |
---|---|

`r_mars` |
Average radius of Mars |

`gm_mars` |
Gravitational constant times the mass of Mars |

`mass_mars` |
Mass of Mars |

`density_mars` |
Average density of Mars |

`g0_mars` |
Gravitational acceleration of Mars at `r_mars` , not including rotation |

`omega_mars` |
Angular rotation rate of Mars |

`f_mars` |
Topographic flattening of Mars |

`a_mars` |
Semi-major axis radius of Mars |

`b_mars` |
Semi-minor axis radius of Mars |

`u0_mars` |
Reference potential of Mars |