This chart shows the use of logarithmic x and y axes. The luminosity of main-sequence stars spans more than eight orders of magnitude, from dim red dwarfs like TRAPPIST-1 to massive O-type stars like Theta¹ Orionis C. On logarithmic axes the mass-luminosity relation appears as a nearly straight line. Switch the axes to linear to see how almost all of the stars collapse into the lower left corner.