The canonical horizontal axis is difficult to develop analytically and is so sometimes replaced by B-V color, an easier quantity to measure than spectral class.
According to this, blue stragglers are separate from their clusters, and the Hess diagram reflects the density of this. The canonical horizontal axis is difficult to develop analytically and is so sometimes replaced by B-V color, an easier quantity to measure than spectral class. The y-axis is usually drawn logarithmically and can be labeled with either luminosity or absolute magnitude. Name this doubly- eponymous astronomical diagram that features a central line for the main sequence and plots several characteristics of stars.
According to this, blue stragglers are separate from their clusters, and the Hess diagram reflects the density of this.
Hertzsprung-Russell diagram