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- Main_sequence abstract "In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or "dwarf" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward gravitational pressure from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, while main-sequence stars below 0.4 solar masses undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 solar masses becoming white dwarfs directly, while stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.".
- Main_sequence thumbnail HRDiagram.png?width=300.
- Main_sequence wikiPageExternalLink evolve.htm.
- Main_sequence wikiPageExternalLink starcolor.
- Main_sequence wikiPageID "19605".
- Main_sequence wikiPageRevisionID "603254853".
- Main_sequence hasPhotoCollection Main_sequence.
- Main_sequence subject Category:Hertzsprung–Russell_classifications.
- Main_sequence subject Category:Main-sequence_stars.
- Main_sequence subject Category:Star_types.
- Main_sequence subject Category:Stellar_evolution.
- Main_sequence type Abstraction100002137.
- Main_sequence type Act100030358.
- Main_sequence type Activity100407535.
- Main_sequence type Categorization101012712.
- Main_sequence type Event100029378.
- Main_sequence type Grouping101012360.
- Main_sequence type Hertzsprung-RussellClassifications.
- Main_sequence type PsychologicalFeature100023100.
- Main_sequence type YagoPermanentlyLocatedEntity.
- Main_sequence comment "In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or "dwarf" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium.".
- Main_sequence label "Ciąg główny".
- Main_sequence label "Hauptreihe".
- Main_sequence label "Hoofdreeks".
- Main_sequence label "Main sequence".
- Main_sequence label "Secuencia principal".
- Main_sequence label "Sequenza principale".
- Main_sequence label "Sequência principal".
- Main_sequence label "Séquence principale".
- Main_sequence label "Главная последовательность".
- Main_sequence label "النسق الأساسي".
- Main_sequence label "主序星".
- Main_sequence label "主系列星".
- Main_sequence sameAs Hlavní_posloupnost.
- Main_sequence sameAs Hauptreihe.
- Main_sequence sameAs Κύρια_ακολουθία.
- Main_sequence sameAs Secuencia_principal.
- Main_sequence sameAs Séquence_principale.
- Main_sequence sameAs Deret_utama.
- Main_sequence sameAs Sequenza_principale.
- Main_sequence sameAs 主系列星.
- Main_sequence sameAs 주계열성.
- Main_sequence sameAs Hoofdreeks.
- Main_sequence sameAs Ciąg_główny.
- Main_sequence sameAs Sequência_principal.
- Main_sequence sameAs m.04ypp.
- Main_sequence sameAs Q3450.
- Main_sequence sameAs Q3450.
- Main_sequence sameAs Main_sequence.
- Main_sequence wasDerivedFrom Main_sequence?oldid=603254853.
- Main_sequence depiction HRDiagram.png.
- Main_sequence isPrimaryTopicOf Main_sequence.
