An Etymological Dictionary of Astronomy and Astrophysics
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A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.

→ chemical; → evolution.

Any process of formation or growth; development; a process of gradual, progressive change; a product of such development; something evolved.
Astro.: A continuous and progressive change according to certain laws and by means of acting physical forces.
Biology: A process of development in which a living organism, through major environmental changes, becomes more and more complex by the differentiation of its parts.

Verbal noun of → evolve.

Of, pertaining to, or in accordance with a theory of evolution.

Adjective of → evolution.

The stellar mass based on → effective temperature and → luminosity, as derived from → evolutionary tracks.

→ evolutionary; → mass.

A model, based on theoretical calculations, which predicts the behavior of an astronomical entity (stars, galaxies, Universe) over time.

→ evolutionary; → model.

A particular step or phase in the evolution of an astronomical object.

→ evolutionary; → stage.

The characteristic time it takes an evolving astronomical object to pass from a step to another.

→ evolutionary; → time scale.

In a theoretical → Hertzsprung-Russell diagram, the path taken by an evolving star.

→ evolutionary; → track.

The movement of a celestial body which is in orbit around another. It is often measured as the → orbital period.

Verbal noun of → revolve.

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.

→ sidereal; → revolution; → period.

The gradual changes in physical state (spectrum, luminosity, temperature) and chemical composition that occurs during the life of a star.

→ stellar; → evolution.