# Standard gravitational parameters (μ = GM) in m³/s²
# Source: https://en.wikipedia.org/wiki/Standard_gravitational_parameter
# Uncertain digits (parenthetical notation) are truncated.

SUN_MU     = 1.32712440042e+20
MERCURY_MU = 2.2031870799e+13
VENUS_MU   = 3.24858592e+14
EARTH_MU   = 3.986004418e+14
MOON_MU    = 4.902800118e+12
MARS_MU    = 4.282837e+13
CERES_MU   = 6.26325e+10
JUPITER_MU = 1.26686534e+17
SATURN_MU  = 3.7931187e+16
URANUS_MU  = 5.793939e+15
NEPTUNE_MU = 6.836529e+15
PLUTO_MU   = 8.71e+11
ERIS_MU    = 1.108e+12

# Earth J2 perturbation parameter (μ × J2 × R_E²) in m⁵/s²
# Converted from 1.75553 × 10¹⁰ km⁵/s² (× 10¹⁵ m⁵/km⁵)
EARTH_J2   = 1.75553e+25

# Earth mean (arithmetic) radius in meters, as per IUGG
EARTH_MEAN_RADIUS = 6_371_008.7714

# WGS84 ellipsoid defining parameters
# Source: NGA.STND.0036_1.0.0_WGS84 (2014)
EARTH_SEMI_MAJOR_AXIS    = 6_378_137.0       # m  (semi-major axis, a)
EARTH_INVERSE_FLATTENING = 298.257223563      # dimensionless (1/f)