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
This is a phase of stellar evolution undergone by intermediate-mass stars, i.e. those with masses 0.8 M⊙ < < 8 M⊙, a range which encompasses the majority of stars in the Galaxy, including our Sun.
The horizontal branches of some globular clusters have extended blue tails (at the high-temperature end of the branch) which dip to lower luminosities, whose stars are called extreme horizontal branch stars.
horizontal branch Region of the Hertzsprung-Russell diagram where post-main sequence stars again reach hydrostatic equilibrium. At this point, the star is burning helium in its core, and hydrogen in a shell surrounding the core.
Horizontal Branch
In the H-R diagram of a globular cluster, the sequence of stars extending from the red giants toward the blue side of the diagram; includes RR Lyrae stars.
Horoscope ...
Horizontal Branch Star - A star which is undergoing helium fusion in its core and hydrogen fusion in a shell surrounding the core ...
Horizontal Branch Star
A metal-poor star, similar in mass to the Sun, that fuses helium into carbon and oxygen at its core. Such stars range in color from blue to yellow. RR Lyrae stars are horizontal-branch stars.
The Horizontal Branch
The energy released by the helium flash raises the core temperature to the point where it is no longer degenerate. It thus starts to behave again as an ideal gas so can expand and cool.
Horizontal branch stars are characterized by helium core burning and hydrogen burning in a shell surrounding the core.
2. What element makes up the core of a massive star just before it goes supernova?
Iron.
Horizontal Branch
None of the energy from the helium core flash will make it out of the star. It will act to revert the core back to an ideal gas state, and expand it.
horizontal branch Region of the H-R diagram where post-main sequence stars again reach hydrostatic equilibrium. At this point, the star is burning helium in its core, and hydrogen in a shell surrounding the core.
horizontal branch - (n.)
A sequence of stars in the H-R diagram of a globular cluster, extending horizontally across the diagram to the left from the red-giant region.
HORIZONTAL BRANCH
The horizontal branch is a part of the Hertzsprung -Russell (H-R) diagram that represents stars that burn helium in thier cores. These mostly large stars lie along the top of the H-R diagram.
horizontal branch stars (NASA Thesaurus) Horizontal strips of stars on the Hertzsprung-Russell diagram of globular clusters to the left of the red giant branch.
An isolated galaxy which does not belong to any cluster of galaxies. The ratio of galaxies in clusters to field galaxies is about 23:1. [H76]
Field Horizontal Branch Stars ...
RR LYRAE STAR - Variable, horizontal branch stars with periods ranging from a few hours to 2 days, and optical brightnesses that typically vary between 0.3 and 2 magnitudes.
These are lower-luminosity stars, where the instability strip crosses the horizontal branch. They may appear on cluster H-R diagrams by omission in the "RR Lyrae gap", since variables are usually not plotted.
The Sun will become a horizontal branch star, burning helium in its core in a stable fashion much like it burns hydrogen today. The helium-fusing stage will last only 100 million years.
Platais and colleague's new census of some 60 thousand of the cluster's stars revealed that NGC 6791 contains several luminous stars belonging to the so-called classical horizontal branch.
The core helium fusing phase of a star's life is called the horizontal branch in metal-poor stars, so named because these stars lie on a nearly horizontal line in the Hertzsprung-Russell diagram of many star clusters.
lands on "Horizontal Branch" (HB)
He fuel exhausted in core
He & H shells burning, very powerful
envelope expands and cools ---
up RGB second time (AGB)
red supergiant (Rstar ~ 5 AU, L star ~ 10 4 Lsun ) ...
The most accurate age for a cluster is found from fitting the entire cluster HR diagram (main sequence, sub-giant, red giant, and horizontal branch) to a stellar evolution model of a specific age and chemical composition.
extrasolar planets, detection
extrasolar planets, searches
extreme horizontal branch star (EHB star)
extreme Population I star
extremely large telescope
extrinsic variable
eye relief
eyepiece
Eyes, The (NGC 4435 and 4438) ...
 See also: Star, Horizon, Luminosity, Temperature, Sun
|
