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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 ...
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
The name derives from the shape of the evolutionary track on a Hertzsprung–Russell diagram which forms a loop towards the blue (i.e. hotter) side of the diagram, to a place called the blue giant branch. [1] Blue loops can occur for red supergiants, red-giant branch stars, or asymptotic giant branch stars. Some stars may undergo more than one ...
The red-giant branch variable star Gamma Crucis is the nearest M-class giant star at 88 light-years. [25] The K1.5 red-giant branch star Arcturus is 36 light-years away. [ 26 ]
The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha process) and by hydrogen fusion (via the CNO cycle) in a shell surrounding the core.
The evolutionary track of the star will then carry it toward the left of the HR diagram as the surface temperature increases under the new equilibrium. The result is a sharp discontinuity in the evolutionary track of the star on the HR diagram. [2] This discontinuity is called the tip of the red-giant branch.
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Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.