colour excess

Quick Reference


The difference, due to interstellar absorption, between the observed colour of a star and its intrinsic colour index. Interstellar absorption decreases towards longer wavelengths, so its effect is always to make a star appear redder; colour excesses are therefore always positive. The symbol for the colour excess in B − V is E(B − V), and similarly for other colours.

Subjects: Astronomy and Astrophysics.

Reference entries