Horizontal branch

(astronomy) A region in the Hertzsprung-Russell diagram of a typical globular cluster that extends in the blue direction from the giant branch at an absolute bolometric magnitude of 0.3 and consists of stars that are burning helium in their cores and hydrogen in their surrounding envelopes.

A branch drain with a horizontal extension from a waste, soil, or vent stack, or from a building drain, which receives the discharge from a single fixture or a group of fixtures and conducts it to the soil or waste stack or to the building drain.

horizontal branch

The horizontal branch (HB) is a stage of stellar evolution which 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 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 Lyrae stars.

A related class of stars are those belonging to the so-called red clump, which are the (relatively younger) population I counterparts to HB stars (which belong to population II).

See also

• Asymptotic Giant Branch
• Red clump

v • d • e Star Evolution Formation  · Pre-main sequence  · Main sequence  · Horizontal branch  · Asymptotic giant branch  · Instability strip  · Red clump  · Planetary nebula  · Protoplanetary nebula  · Luminous blue variable  · Wolf-Rayet star  · Supernova impostor  · Supernova  · Hypernova  · Hertzsprung–Russell diagram Protostars Molecular cloud  · Bok globule  · Young stellar object  · Herbig–Haro object  · Hayashi track  · Hayashi limit  · Henyey track  · T Tauri star · Herbig Ae/Be star Types Subdwarf  · Dwarf (Blue  · Orange  · Red  · Yellow)  · Subgiant  · Giant (Red)  · Bright giant  · Supergiant (Blue  · Red  · Yellow)  · Hypergiant (Yellow)  · Blue straggler  · Shell  · Carbon (CH) · Barium  · S-type  · Peculiar  · Technetium  · Mercury-manganese  · Variable Remnants White dwarf  · Neutron star (Pulsar · Magnetar)  · Stellar black hole  · Compact star (Exotic star  · Quark star  · Preon star  · Q star)  · Black dwarf Failed stars Brown dwarf  · Sub-brown dwarf  · Planetar Structure Core · Convection zone · Radiation zone · Photosphere · Chromosphere · Corona · Stellar wind · Stellar wind bubble  · Magnetic field · Asteroseismology  · Solar-like oscillations  · Eddington luminosity Nucleosynthesis S-process  · Alpha process  · Triple-alpha process  · Proton-proton chain  · CNO cycle  · Carbon burning  · Neon burning  · Oxygen burning  · Silicon burning  · Helium flash Properties Classification  · Effective temperature  · Kinematics (Proper motion · Radial velocity)  · Mass  · Metallicity  · Microturbulence  · Planetary system · Rotation · Star system (Binary  · Multiple)  · Dynamics  · UBV color  · Designation  · Absolute magnitude  · Apparent magnitude Lists Star names  · Most massive  · Least massive  · Largest  · Brightest  · Most luminous  · Nearest  · Brown dwarfs  · Timeline of stellar astronomy

This giant star-related article is a stub. You can help Wikipedia by expanding it.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)