ASTR 103 - Astronomy

Glossary - V

Van Allen radiation belts

Two principal zones of high intensity radiation surrounding Earth within the magnetosphere; named after their discovered.

variable star

Any star that exhibits intrinsic changes in light.

velocity curve

Plot of the change in radial velocity (Doppler shift) against time.

vernal equinox

Point of intersection on the sky between the Sun's path (ecliptic) and the celestial equator, reached by the Sun on about March 21.

very-long-baseline interferometry

Technique of employing two or more widely separated radio telescopes to observe simultaneously a minute angular source in order to obtain a high degree of resolution.

visual binary

Physically related double star whose components can be resolved in a telescope.

visual magnitude

Magnitude corresponding to the measurement of the visual light in the approximate spectral range of 4000-7000 angstroms.