A Cepheld aris a type of variable , which means its brightness is not constant The relationship between the brightness of a Cephed war and its period , or length of ts puses given by M -2.78los P ) - 135 , where is the about magnade or brightness of the stand the number of days required for the star to complete recycle What is the absolute magnitude of a starthathan a period of 45 days ? Use a actor Round your answer to the nearest hundred 596​