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  2. Stellar classification - Wikipedia

    en.wikipedia.org/wiki/Stellar_classification

    Class G main-sequence stars make up about 7.5%, nearly one in thirteen, of the main-sequence stars in the solar neighborhood. There are 21 G-type stars within 10pc. [c] [11] Class G contains the "Yellow Evolutionary Void". [84] Supergiant stars often swing between O or B (blue) and K or M (red).

  3. Hertzsprung–Russell diagram - Wikipedia

    en.wikipedia.org/wiki/Hertzsprung–Russell_diagram

    Theoretical calculations of stellar structure and the evolution of stars produce plots that match those from observations. This type of diagram could be called temperature-luminosity diagram, but this term is hardly ever used; when the distinction is made, this form is called the theoretical Hertzsprung–Russell diagram instead. A peculiar ...

  4. Luminosity - Wikipedia

    en.wikipedia.org/wiki/Luminosity

    Luminosity is an absolute measure of radiated electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. [1] [2] In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical objects. [3] [4]

  5. Stellar structure - Wikipedia

    en.wikipedia.org/wiki/Stellar_structure

    In forming the stellar structure equations (exploiting the assumed spherical symmetry), one considers the matter density (), temperature (), total pressure (matter plus radiation) (), luminosity (), and energy generation rate per unit mass () in a spherical shell of a thickness at a distance from the center of the star.

  6. K-type main-sequence star - Wikipedia

    en.wikipedia.org/wiki/K-type_main-sequence_star

    A K-type main-sequence star, also referred to as a K-type dwarf, or orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ("red dwarfs") and yellow/white G-type main-sequence stars.

  7. Standard solar model - Wikipedia

    en.wikipedia.org/wiki/Standard_solar_model

    For simplicity, the stellar structure equations are written without explicit time dependence, with the exception of the luminosity gradient equation: = Here L is the luminosity, ε is the nuclear energy generation rate per unit mass and ε ν is the luminosity due to neutrino emission (see below for the other quantities). The slow evolution of ...

  8. Initial mass function - Wikipedia

    en.wikipedia.org/wiki/Initial_mass_function

    IMF and PDMF can be linked through the "stellar creation function". [2] Stellar creation function is defined as the number of stars per unit volume of space in a mass range and a time interval. In the case that all the main sequence stars have greater lifetimes than the galaxy, IMF and PDMF are equivalent.

  9. Astrophysics - Wikipedia

    en.wikipedia.org/wiki/Astrophysics

    Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. [1] [2] As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space—what they are, rather than where they are", [3] which is studied ...