HIP 107 vs HIP 124

Colour is the plainest difference between them: HIP 107 is an M-type star and HIP 124 an F-type star in Cassiopeia, most of the Harvard sequence apart. The two are near-identical in apparent brightness, HIP 107 at magnitude +5.53 and HIP 124 at +5.58. Absolute magnitudes of −4.29 for HIP 124 and −0.58 for HIP 107 put a factor near 30 between their true outputs.