๐Ÿชintro to astronomy review

Reddening

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025

Definition

Reddening is the process in which light from stars or other celestial objects appears redder than it actually is due to scattering by interstellar dust. This effect occurs because shorter wavelengths of light (blue) are scattered more than longer wavelengths (red).

5 Must Know Facts For Your Next Test

  1. Reddening is caused primarily by interstellar dust grains that scatter and absorb light.
  2. This phenomenon can affect astronomical observations, making stars appear cooler and farther away than they are.
  3. The amount of reddening is quantified using the color excess, denoted as E(B-V).
  4. Reddening does not change the intrinsic luminosity of a star but alters its observed color and brightness.
  5. Astronomers use models of reddening to correct their observations and better understand the properties of celestial objects.

Review Questions

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