An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3 Search : supra-
supra-
  فراز، بالا، ابر-   
farâz, bâlâ, abar-

Fr.: supra-   

A prefix denoting "over, above, beyond, greater than."

From L. supra "above, over, before, beyond," → super-.

Farâz "above, up, upon," → height; bâlâ "above, up, high," → height; abar-, → super-.

supra-Eddington layer
  لایه‌ی ِ ابر-ادینگتونی   
lâye-ye abar-Eddingtoni

Fr.: couche super-eddingtonienne   

In some stellar models, particularly for evolved → massive stars, such as → red supergiants, → Luminous Blue Variables, and → Wolf-Rayet stars, an outermost layer of the stellar envelope where the luminosity might exceed the → Eddington limit. This is due to the → opacity peak produced by the variation in the ionization level of hydrogen in the outer → convective envelope, beneath the surface, of very luminous stars. The opacity peak generates supra-Eddington layers and density inversion. The high opacity decreases the Eddington luminosity in these layers, possibly to fainter levels than the actual stellar luminosity. As a result, the → radiative acceleration exceeds the → gravitational acceleration leading to → mass loss enhancement (see, e.g., A. Maeder, Physics, Formation and Evolution of Rotating Stars, Springer, 2009).

supra-; → Eddington limit; → layer.

supra-horizontal branch star
  ستاره‌ی ِ فراز ِ شاخه‌ی ِ افقی   
setâre-ye farâz-e šâxe-ye ofoqi

Fr.: étoile au-dessus de la branche horizontale   

A member of a rare class of objects found in → globular clusters to lie about one magnitude above and to the blue part of the → horizontal branch. These stars are identified as post → EHB stars on their way from to the → asymptotic giant branch.

supra-; → horizontal; → branch; → star.