Although a star might look brighter than the sun, a comparison of its magnitude might prove that they have the same real brightness.

Although a star might look brighter than the Sun, a comparison of its absolute magnitude might help prove that they have the same real brightness.
Absolute magnitude is a concept that compares the absolute brightness of celestial objects. The absolute magnitude of an object is defined as the apparent magnitude it would have if it were viewed at a standard distance of 10 parsecs (32.6 light-years) with no dimming of its light. The more luminous an object, the smaller the numerical value of its absolute magnitude.