Articles in astronomy give the colors of stars as a number, called color index.
How do you turn this number into a real color?
The color index (CI) is usually
CI = mB - mV
where mB is the blue color magnitude of the star and mV the visible color magnitude. As the magnitude increases with decreasing brightness a star with a smaller index will be more blue and a star with a larger index more red. The following table should help you do the translation:
|Color Index||Spectral Class||Color|
|0.15||A5||White with bluish tinge|
This table is only valid for the B-V (or Blue minus Visible) color index. Often astronomers use other color indexes such as U-B (Ultraviolet minus Blue) or H-K (H-band minus K-band) indexes.
This page updated on June 27, 2015