An Etymological Dictionary of Astronomy and Astrophysics
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The evolutionary path of a star that has exhausted its available hydrogen content in the core, between the → main-sequence turnoff and the → helium flash.

→ red giant; → branch.

A technique for deriving extragalactic distances which uses the → luminosity of the brightest → red giant branch stars in old → stellar populations as a → standard candle. For old (> 2-3 Gyr), → metal-poor ([Fe/H] < -0.7) stellar populations, this luminosity is relatively well determined, and the → absolute magnitude of these stars in the I band is roughly constant (M_I = -4.1 ± 0.1).

→ tip; → red giant; → branch; → method.