fargašt-e šimiyâyi (#)
Fr.: évolution chimique
A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.
Any process of formation or growth; development; a process of gradual, progressive change;
a product of such development; something evolved.
Verbal noun of → evolve.
Of, pertaining to, or in accordance with a theory of evolution.
Adjective of → evolution.
jerm-e fargašti (#)
Fr.: masse évolutive
model-e fargašt (#)
Fr.: modèle d'évolution
A model, based on theoretical calculations, which predicts the behavior of an astronomical entity (stars, galaxies, Universe) over time.
Fr.: étape d'évolution
A particular step or phase in the evolution of an astronomical object.
evolutionary time scale
Fr.: échelle de temps d'évolution
The characteristic time it takes an evolving astronomical object to pass from a step to another.
Fr.: trajet évolutif
In a theoretical → Hertzsprung-Russell diagram, the path taken by an evolving star.
The movement of a celestial body which is in orbit around another. It is often measured as the → orbital period.
Verbal noun of → revolve.
sidereal revolution period
dowre-ye gardeš-e axtari (#)
Fr.: période de révolution sidérale
The time taken by a planet or satellite to complete one revolution about its primary with respect to stars. For Earth, same as → sidereal year. Sidereal periods of the solar system planets, interms of the sidereal year, are as follows: Mercury 0.240846 (87.9691 days); Venus 0.615 (225 days); Earth 1 (365.25636 solar days); Mars 1.881; Jupiter 11.86; Satrurn 29.46; Uranus 84.01; and Neptune 164.8. That of the Moon is 0.0748 (27.32 days) and for → Sedna 12050.
Fr.: évolution stellaire
The gradual changes in physical state (spectrum, luminosity, temperature) and chemical composition that occurs during the life of a star.