Changes

:d : a person who is preeminent in a particular field

:d : a person who is preeminent in a particular field

==Description==

==Description==

A '''star''' is a massive, luminous ball of [[plasma]] that is held together by [[gravity]]. The nearest star to [[Earth]] is the [[Sun]], which is the [[source]] of most of the [[energy]] on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun. Historically, the most prominent stars on the [[celestial]] [[sphere]] were grouped together into [http://en.wikipedia.org/wiki/Constellation constellations], and the brightest stars gained proper [[names]]. Extensive [[Astrometry|catalogues]] of stars have been assembled by astronomers, which provide [[standardized]] star designations.

A '''star''' is a massive, luminous ball of [http://en.wikipedia.org/wiki/Plasma_(physics) plasma] that is held together by [[gravity]]. The nearest star to [[Earth]] is the [[Sun]], which is the [[source]] of most of the [[energy]] on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun. Historically, the most prominent stars on the [[celestial]] [[sphere]] were grouped together into [http://en.wikipedia.org/wiki/Constellation constellations], and the brightest stars gained proper [[names]]. Extensive [[Astrometry|catalogues]] of stars have been assembled by astronomers, which provide [[standardized]] star designations.

For most of its life, a star shines due to [http://en.wikipedia.org/wiki/Thermonuclear_fusion thermonuclear fusion] in its core releasing [[energy]] that traverses the star's interior and then radiates into outer [[space]]. Almost all elements heavier than [http://en.wikipedia.org/wiki/Hydrogen hydrogen] and [http://en.wikipedia.org/wiki/Helium helium] were [[created]] by [[fusion]] processes in stars. [[Astronomers]] can determine the [[mass]], age, [[Chemistry|chemical]] composition and many other properties of a star by observing its [[spectrum]], [[luminosity]] and [[motion]] through [[space]]. The [[total]] [[mass]] of a star is the principal determinant in its [[evolution]] and [[eventual]] [[Destiny|fate]]. Other characteristics of a star are determined by its [[evolutionary]] [[history]], including the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a [http://en.wikipedia.org/wiki/Hertzsprung-Russell_diagram Hertzsprung-Russell diagram] (H–R diagram), allows the age and evolutionary state of a star to be determined.

For most of its life, a star shines due to [http://en.wikipedia.org/wiki/Thermonuclear_fusion thermonuclear fusion] in its core releasing [[energy]] that traverses the star's interior and then radiates into outer [[space]]. Almost all elements heavier than [http://en.wikipedia.org/wiki/Hydrogen hydrogen] and [http://en.wikipedia.org/wiki/Helium helium] were [[created]] by [[fusion]] processes in stars. [[Astronomers]] can determine the [[mass]], age, [[Chemistry|chemical]] composition and many other properties of a star by observing its [[spectrum]], [[luminosity]] and [[motion]] through [[space]]. The [[total]] [[mass]] of a star is the principal determinant in its [[evolution]] and [[eventual]] [[Destiny|fate]]. Other characteristics of a star are determined by its [[evolutionary]] [[history]], including the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a [http://en.wikipedia.org/wiki/Hertzsprung-Russell_diagram Hertzsprung-Russell diagram] (H–R diagram), allows the age and evolutionary state of a star to be determined.