An Etymological Dictionary of Astronomy and Astrophysics

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فرهنگ ریشه‌شناختی اخترشناسی-اخترفیزیک

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tip of the red giant branch method (TRGB)
  روش ِ نوک ِ شاخه‌ی غول‌های ِ سرخ  
raveš-e nok-e šâxe-ye qulhâ-ye sorx
Fr.: méthode du haut de la branche des géantes  

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 (MI = -4.1 ± 0.1).

See also: → tip; → red giant; → branch; → method.