- #1
heavystray
- 71
- 0
Hi, in determining the temperature of stars using colour index (U-B,B-V,V-R, etc), why do we need to use the appropriate pairs of filters based on their range of temperature? (this is what i read from wiki)
For cool stars, we use R-I, and for hotter stars, we use B-V. I don't understand how using different pairs of filters make a difference because isn't radiation curve of blackbodies with different temperature have different shape and thus, the values of (B-V, U-B, V-R) will also be different? (I hope you understand what I'm trying too say)
My idea is this has to do with the star's peak wavelength...but i still don't see the justification to that...
your help would be greatly appreciated
For cool stars, we use R-I, and for hotter stars, we use B-V. I don't understand how using different pairs of filters make a difference because isn't radiation curve of blackbodies with different temperature have different shape and thus, the values of (B-V, U-B, V-R) will also be different? (I hope you understand what I'm trying too say)
My idea is this has to do with the star's peak wavelength...but i still don't see the justification to that...
your help would be greatly appreciated