The horizontal branch (HB) is a stage of
stellar evolutionwhich immediately follows the red giant branchin stars whose masses are similar to the Sun's. Horizontal branch stars are powered by helium fusionin the core (via the triple-alpha reaction) and by hydrogen fusion in a shell surrounding the core. The horizontal branch is so named because HB stars lie along a roughly horizontal line in a color-magnitude diagram. Many horizontal branch stars pulsate and these are known as RR Lyraestars.
A related class of stars are those belonging to the so-called
red clump, which are the (relatively younger) population Icounterparts to HB stars (which belong to population II).
Asymptotic Giant Branch
Wikimedia Foundation. 2010.
Look at other dictionaries:
Branch — A branch (American English IPAEng|ˈbræntʃ, British English IPAEng|ˈbrɑːntʃ) or tree branch (sometimes referred to in botany as a ramus) is a woody structural member connected to but not part of the central trunk of a tree (or sometimes a shrub).… … Wikipedia
horizontal — /ˌhɒrɪ zɒnt(ə)l/ adjective at the same level or with the same status ● Her new job is a horizontal move into a different branch of the business … Marketing dictionary in english
Rama horizontal — Saltar a navegación, búsqueda La rama horizontal (RH, en inglés horizontal branch) es una de las fases tardías de la evolución estelar de las estrellas de masa intermedia (0,5 MSol < M < 9 10 MSol) y baja metalicidad. Esta fase recibe su … Wikipedia Español
Asymptotic giant branch — The asymptotic giant branch is the region of the Hertzsprung Russell diagram populated by evolving low to medium mass stars. This is a period of stellar evolution undertaken by all low to intermediate mass stars (0.6 10 solar masses) late in… … Wikipedia
Communications and Electronics Branch — The cap badge of the Communications and Electronics Branch. Active 1968 Country … Wikipedia
United States Army Aviation Branch — Infobox military aviation unit unit name= Aviation Branch caption= United States Army Aviation Branch Plaque dates= 1983 Present country= United States allegiance= branch= US Army type=Aviation role= size= command structure= garrison=Fort Rucker … Wikipedia
Electrical and Mechanical Engineering Branch — Infobox Military Unit unit name=Electrical and Mechanical Engineering Branch caption= dates=15 May 1944 present country=Canada allegiance= branch= type=Canadian Forces personnel branch role= size= command structure= current commander= garrison=… … Wikipedia
List of astronomy acronyms — This is a compilation of acronyms commonly used in astronomy. Most of the acronyms are drawn from professional astronomy and are used quite frequently in scientific publications. However, a few of these acronyms are frequently used by the general … Wikipedia
Evolución estelar — Saltar a navegación, búsqueda En astronomía, se denomina evolución estelar a la secuencia de cambios que una estrella experimenta a lo largo de su existencia. Durante mucho tiempo se pensó que las estrellas eran enormes bolas de fuego perpetuo.… … Wikipedia Español
Hertzsprung–Russell diagram — Hertzsprung–Russell diagram with 22,000 stars plotted from the Hipparcos catalog and 1,000 from the Gliese catalog of nearby stars. Stars tend to fall only into certain regions of the diagram. The most predominant is the diagonal, going from… … Wikipedia