In: Physics
Astronomers can measure the temperature of a star by comparing its brightness in blue and yellow light. Does reddening by interstellar dust affect a star's temperature measurement, and if so, how?
Astronomers can measure the temperature of a star by comparing its brightness in blue & yellow light.
The typical size of an interstellar dust grain means that they scatter short wavelengths most efficiently. A relatively more blue light is removed from the star's spectrum after passing through the cloud and it appears redder when viewed from behind the cloud. This process is called an "interstellar reddening".
Yes, reddening by an interstellar dust which affect a star's temperature measurement.
Explanation : An absorption of starlight by interstellar dust can cause stars to appear fainter than they should and also they cause us to overestimate their distance or underestimate their luminosity.
In addition, an interstellar reddening can cause stars to appear redder than they should. Since colours as measured by the colour index which are often used to infer temperature and the temperature can also be underestimated.
Interstellar dust can be detected which given below as :
(i) when it blocks the light of stars behind it
(ii) when it scatters the light from nearby stars
(iii) it makes distant stars look both redder and fainter