hurmarkazi (#), xoršid markazi (#)
keyhânšenâsi-ye hurmarkazi (#)
Fr.: cosmologie héliocentrique
A model of the Universe in which the Sun was centrally located.
heliocentric gravitational constant
pâyâ-ye gerâneši-ye hur-markazi
Fr.: constante gravitationnelle héliocentrique
Heliocentric Julian Date
gâhdâd-e žulian-e hurmarkazi
Fr.: date julienne héliocentrique
The → Julian Date referenced to the center of the → Sun. Since the Earth revolves around the Sun, and since light travels at a finite speed, observations of a given object taken at different positions in the Earth's orbit are not equivalent, and so a correction for Earth's orbit around the Sun is required. Left uncorrected, the time of an observational event measured by Earth clocks will vary by 16.6 minute over the course of a year. If not properly accounted for, this can lead to a spurious signal in a → periodogram.
Fr.: parallaxe héliocentrique
The parallax of a celestial body when viewed from two points in the Earth's orbit around the Sun. More specifically, the angular difference in a celestial object's position as seen from the center of the Sun and the center of the Earth. Also called → annual parallax.
Fr.: système héliocentrique
A system in which the Sun is assumed to lie at its central point while the Earth and other bodies revolve around it.