Red clump

Red Clump Stars (English translation Red clump stars) are developed metal-rich stars with a helium- burning core in the Hertzsprung -Russell diagram and meet the stars of the horizontal branch of the population II you will be due to the low dependence of their luminosity from the metallicity of astronomical distance determination uses.

Development

After the end of central hydrogen burning on the main sequence at intermediate-mass stars initially developed with 0.5 to 2.5 solar masses, a bowl-shaped hydrogen burning, while the ashes of thermonuclear reactions accumulates in the core of the star. The star evolves along the Red giant branch to higher Leuchkräften and low effective temperatures. The pressure and the temperature in the core rises until a stable helium burning fire. Depending on the metallicity of star metal-poor stars wander due to the low opacity in the region of higher temperatures and form a Horizonalast in the color-magnitude diagram. Metal-rich stars of Population I, however, remain and form red giants in the HR diagram occupied a strong red clump, as the stars remain in this position during the phase of central helium burning.

Distance determination

In the infrared, the absolute magnitudes of the Red Clump Stars are only a small scatter. The absolute magnitude MK is -1.54 to -1.57 over an age range from 0.31 to 8 billion years for solar abundances. This low scattering in combination with a low absorbance in the mid-infrared makes Red Clump stars to a preferred means of determining the distance. They are used for analysis of structures within the Milky Way and used the local group.

Itemization

• Star class