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  2. Hertzsprung–Russell diagram - Wikipedia

    en.wikipedia.org/wiki/Hertzsprung–Russell_diagram

    An observational Hertzsprung–Russell diagram with 22,000 ... on the horizontal axis and the ... Russell diagram to be annotated with known conventional ...

  3. Instability strip - Wikipedia

    en.wikipedia.org/wiki/Instability_strip

    The unqualified term instability strip usually refers to a region of the Hertzsprung–Russell diagram largely occupied by several related classes of pulsating variable stars: [1] Delta Scuti variables, SX Phoenicis variables, and rapidly oscillating Ap stars (roAps) near the main sequence; RR Lyrae variables where it intersects the horizontal branch; and the Cepheid variables where it crosses ...

  4. Main sequence - Wikipedia

    en.wikipedia.org/wiki/Main_sequence

    The path which the star follows across the HR diagram is called an evolutionary track. [57] H–R diagram for two open clusters: NGC 188 (blue) is older and shows a lower turn off from the main sequence than M67 (yellow). The dots outside the two sequences are mostly foreground and background stars with no relation to the clusters.

  5. Stellar isochrone - Wikipedia

    en.wikipedia.org/wiki/Stellar_isochrone

    In stellar evolution, an isochrone is a curve on the Hertzsprung-Russell diagram, representing a population of stars of the same age but with different mass. [1] The Hertzsprung-Russell diagram plots a star's luminosity against its temperature, or equivalently, its color. Stars change their positions on the HR diagram throughout their life.

  6. Henyey track - Wikipedia

    en.wikipedia.org/wiki/Henyey_track

    An HR Diagram of PMS stars with different masses. The Hayashi Track is depicted as vertical lines, while the Henyey are horizontal. Higher mass stars spend very little time on the Hayashi Track, while the lowest mass stars never reach the Heyney Track, with a gradient seen of time spent on each track as the mass increases.

  7. Subgiant - Wikipedia

    en.wikipedia.org/wiki/Subgiant

    A Hertzsprung–Russell (H–R) diagram is a scatter plot of stars with temperature or spectral type on the x-axis and absolute magnitude or luminosity on the y-axis. H–R diagrams of all stars, show a clear diagonal main sequence band containing the majority of stars, a significant number of red giants (and white dwarfs if sufficiently faint ...

  8. Red-giant branch - Wikipedia

    en.wikipedia.org/wiki/Red-giant_branch

    The term red-giant branch came into use during the 1940s and 1950s, although initially just as a general term to refer to the red-giant region of the Hertzsprung–Russell diagram. Although the basis of a thermonuclear main-sequence lifetime, followed by a thermodynamic contraction phase to a white dwarf was understood by 1940, the internal ...

  9. Hayashi track - Wikipedia

    en.wikipedia.org/wiki/Hayashi_track

    The diagram at the top of this article shows numerically computed stellar evolution tracks for various masses. The vertical portions of each track is the Hayashi track. The endpoints of each track lie on the main sequence. The horizontal segments for higher-mass stars show the Henyey track.