cubic astronomical unit per square day
Standard gravitational parameterexact by definition
The cubic astronomical unit per square day is the unit JPL's planetary ephemerides are computed in, about 4.4849e23 m³/s². It is exact, the astronomical unit being defined as exactly 1.495978707e11 metres since 2012 and the day as exactly 86400 seconds. The Sun's gravitational parameter in these units is 0.00029591220828559, which is the square of the Gaussian gravitational constant.
| 1 | 448,485,860,000,000 |
Gauss chose his constant k in 1809 so that a body orbiting at one astronomical unit would have a convenient period, which effectively defined the astronomical unit through the orbit rather than the other way round. The IAU reversed that in 2012 by fixing the AU as a plain length in metres, so k is now a historical constant rather than a defining one.
One cubic astronomical unit per square day in every standard gravitational parameter unit
| 4.48486e+23 | cubic meter per second squared (m³/s²) | |
| 448,486,000,000,000 | cubic kilometer per second squared (km³/s²) | |
| 1,125,150,000 | terrestrial mass parameter (GMearth) | |
| 3,379.38 | solar mass parameter (GMsun) | |
| 1 | cubic astronomical unit per square day (AU³/d²)this unit |