Changes

==Etymology==

==Etymology==

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] sterre, from [https://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] steorra; akin to Old High German sterno star, Latin stella, [[Greek]] astēr, astron

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] sterre, from [https://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] steorra; akin to Old High German sterno star, Latin stella, [[Greek]] astēr, astron

*Date: before [http://www.wikipedia.org/wiki/11th_Century 12th century]

*Date: before [https://www.wikipedia.org/wiki/11th_Century 12th century]

==Definitions==

==Definitions==

*1 a : a [[natural]] [[luminous]] [[body]] visible in the sky especially at night  

*1 a : a [[natural]] [[luminous]] [[body]] visible in the sky especially at night  

: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 [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.

A '''star''' is a massive, luminous ball of [https://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 [https://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 [https://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 [https://en.wikipedia.org/wiki/Hydrogen hydrogen] and [https://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 [https://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.

A star begins as a collapsing cloud of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily [[converted]] into helium through the [[process]] of nuclear [[fusion]]. The remainder of the star's interior carries [[energy]] away from the core through a combination of [http://en.wikipedia.org/wiki/Radiation radiative] and [http://en.wikipedia.org/wiki/Convection convective] processes. The star's internal pressure prevents it from collapsing further under its own [[gravity]]. Once the hydrogen fuel at the core is exhausted, those stars having at least 0.4 times the mass of the Sun[2] expand to become a [http://en.wikipedia.org/wiki/Red_giant red giant], in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of the [[matter]] into the interstellar environment, where it will form a new [[generation]] of stars with a higher proportion of heavy elements.

A star begins as a collapsing cloud of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily [[converted]] into helium through the [[process]] of nuclear [[fusion]]. The remainder of the star's interior carries [[energy]] away from the core through a combination of [https://en.wikipedia.org/wiki/Radiation radiative] and [https://en.wikipedia.org/wiki/Convection convective] processes. The star's internal pressure prevents it from collapsing further under its own [[gravity]]. Once the hydrogen fuel at the core is exhausted, those stars having at least 0.4 times the mass of the Sun[2] expand to become a [https://en.wikipedia.org/wiki/Red_giant red giant], in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of the [[matter]] into the interstellar environment, where it will form a new [[generation]] of stars with a higher proportion of heavy elements.

[http://en.wikipedia.org/wiki/Binary_star Binary] and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable [[orbits]]. When two such stars have a [[relatively]] close orbit, their gravitational [[interaction]] can have a significant impact on their [[evolution]]. Stars can form part of a much larger gravitationally bound [[structure]], such as a cluster or a [[galaxy]].[http://en.wikipedia.org/wiki/Star]

[https://en.wikipedia.org/wiki/Binary_star Binary] and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable [[orbits]]. When two such stars have a [[relatively]] close orbit, their gravitational [[interaction]] can have a significant impact on their [[evolution]]. Stars can form part of a much larger gravitationally bound [[structure]], such as a cluster or a [[galaxy]].[https://en.wikipedia.org/wiki/Star]

[[Category: Astronomy]]

[[Category: Astronomy]]