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: 13 Search : redden
de-redden
  واسرخیدن   
vâsorxidan

Fr.: dérougir   

To correct the intensity or flux of a spectral line by eliminating the → reddening effect of → interstellar dust.

De-redden, from → de- + redden verb of → red.

Vâsorxidan, from vâ-, → de-, + sorxidan verb of sorx, → red.

de-reddened magnitude
  برز ِ واسرخیده   
borz-e vâsorxidé

Fr.: magnitude dérougie   

A magnitude which has been corrected for the interstellar reddening.

De-reddened, p.p. of → de-redden; → magnitude.

Borz, → magnitude; vâsorxidé p.p. of vâsorxidan, → de-redden.

de-reddening
  واسرخش   
vâsorxeš

Fr.: dérougissement   

The process that de-reddens. The state of being de-reddened.

Verbal noun of → de-redden.

interstellar reddening
  سُرخش ِ اندر-اختری   
sorxeš-e andaraxtari

Fr.: rougissement interstellaire   

The dimming of light during its travel in the → interstellar medium due to absorption by → intervening → dust grains. Since shorter wavelengths are particularly affected, the spectrum of the light is increasingly dominated by the long wavelength end of the spectrum. As a result, the light is "reddened" as it travels through space. Robert J. Trumpler (1886-1956), a Swiss-American astronomer, was the first to produce a definite evidence of the existence of → interstellar extinction and to estimate its magnitude (1930).

interstellar; → reddening.

interstellar reddening curve
  خم ِ سُرخش ِ اندر-اختری   
xam-e sorxeš-e andaraxtari

Fr.: courbe de rougissement interstellaire   

A graph showing the relation between → interstellar absorption (in magnitudes) and wavelength.

interstellar; → reddening; → curve.

redden
  ۱) سُرخیدن؛ ۲) سرخاندن   
1) sorxidan; 2) sorxândan

Fr.: 1) rougir; 2) faire rougir   

1) (v.intr.) Of a spectral line, to reduce in intensity due to absorption by interstellar dust grains.
2) (v.tr.) Of interstellar dust, to absorb the light that passes through it.

Infinitives from → red.

reddened star
  ستاره‌ی ِ سرخیده   
setâre-ye sorxidé

Fr.: étoile rougie   

A star whose light has undergone → reddening.

Reddened, p.p. of → redden; → star.

reddening
  سُرخش   
sorxeš

Fr.: rougissement   

The process by which light from an astronomical object grows red as it travels through interstellar dust. Dust scatters blue light more than red, thus leaving predominantly red light transmitted.

Verbal noun of → redden.

reddening coefficient
  همگر ِ سرخش   
hamgar-e sorxeš

Fr.: coefficient de rougissement   

A dimensionless quantity determined from the comparison of the observed → Balmer decrements with respect to the theoretical values for given physical conditions of electron temperature and density. The reddening coefficient at Hβ is defined as c(Hβ) = log (I(Hβ)/F(Hβ)), where I(Hβ) and F(Hβ) are → de-reddened and reddened fluxes respectively. Also called logarithmic extinction.

reddening; → coefficient.

reddening function
  کریای ِ سرخش   
karyâ-ye sorxeš

Fr.: fonction de rougissement   

The normalized interstellar extinction at a given wavelength. It is defined by f(λ) = A(λ)/A(Hβ) - 1, where A(λ) is the extinction at the given wavelength and A(Hβ) the extinction at Hβ, with f(Hβ) = 0. It is used to → de-redden observed fluxes: I(λ)/I(Hβ) = F(λ)/F(Hβ).10c(Hβ).f(λ), where I represents the flux in the absence of extinction and F the observed flux affected by extinction, c(Hβ) being the → reddening coefficient.

reddening; → function.

reddening parameter
  پارامون ِ سرخش   
pârâmun-e sorxeš

Fr.: paramètre de rougissement   

A dimensionless quantity characterizing the → interstellar extinction, defined by the total-to-selective extinction ratio: RV = AV/E(B-V). The typical value found for the reddening parameter in the Milky Way is RV ~ 3.1, but it is known to vary from one line of sight to another, from values as 2 to as large as 6. Very large → dust grains would produce extinction with RV → ∞.

reddening; → parameter.

reddening vector
  بُردار ِ سرخش   
bordâr-e sorxeš

Fr.: vecteur de rougissement   

A vector indicating the direction in which interstellar reddening moves the position of a star in a multi-dimensional space of color indices.

reddening; → vector.

unreddened star
  ستاره‌ی ِ ناسرخیده   
setâre-ye nâsorxidé

Fr.: étoile non rougie   

A star whose light is not affected by→ interstellar absorption. → reddening

un-; → reddened star.