Rigel

Rigel is a blue-white supergiant star in Orion, marking the constellation’s lower-right corner. It is a luminous, massive multiple-star system roughly 860 light-years from Earth.

Blue supergiant: A very luminous, massive star with a high surface temperature and blue or blue-white color. Rigel is classified as a blue supergiant, a rare and short-lived stellar stage.
Stellar evolution: The changes in a star’s structure and properties over its lifetime. Rigel’s supergiant state is a brief phase in the evolution of a massive star.
Rigel B: The close companion to Rigel A, itself a pair of hot stars. This component makes Rigel a multiple-star system rather than a solitary supergiant.
Stellar parallax: The apparent annual shift of a nearby star against distant background objects as Earth orbits the Sun. Parallax measurements help establish Rigel’s distance, though its large distance makes precision challenging.
Stellar classification: A system for grouping stars by properties such as spectrum, temperature, and luminosity. Rigel’s spectral type and luminosity class summarize its measured properties.
Spectroscopy: The study of matter and radiation through their interaction across wavelengths. Rigel’s spectrum reveals its temperature, composition, and motion.
Betelgeuse: A red supergiant star that marks Orion’s upper-left corner. Its cool red appearance contrasts with Rigel’s hot blue-white light.
Cepheid variable: A pulsating star whose period of brightness variation is related to its intrinsic luminosity. Rigel varies, but it is not a Cepheid and does not serve as a standard candle by that relation.
Luminosity: The total energy a celestial object emits per unit time. Rigel’s intrinsic luminosity distinguishes it from stars that merely look bright nearby.
Spectral line: A narrow range of wavelengths emitted or absorbed by atoms or molecules. Shifts in Rigel’s spectral lines help measure its radial velocity.

Linked from 5 pages