Assertion: orbital speed | /r/HasProperty | approximated
Facets:
value: from observations of the orbital period
type: OTHER
Source sentences:
text: For orbits with small eccentricity, the length of the orbit is close to that of a circular one, and the mean orbital speed can be approximated either from observations of the orbital period and the semimajor axis of its orbit, or from knowledge of the masses of the two bodies and the semimajor axis.