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Luminosity estimates[edit]Compared to the Milky Way, the Andromeda Galaxy appears to have predominantly older stars withages >7×109years.[53][clarification needed]The estimatedluminosityof the Andromeda Galaxy, ~2.6×1010L, isabout 25% higher than that of our own galaxy.[64][65]However, the galaxy has a highinclinationas seenfrom Earth and itsinterstellar dustabsorbs an unknown amount of light, so it is difficult to estimate itsactual brightness and other authors have given other values for the luminosity of the AndromedaGalaxy (some authors even propose it is the second-brightest galaxy within a radius of10mega-parsecsof the Milky Way, after theSombrero Galaxy,[66]with an absolute magnitude ofaround -22.21[d]or close[67]).An estimation done with the help ofSpitzer Space Telescopepublished in 2010 suggestsanabsolute magnitude(in the blue) of −20.89 (that with acolor indexof +0.63 translates to anabsolute visual magnitude of −21.52,[a]compared to −20.9 for the Milky Way), and a total luminosityin thatwavelengthof 3.64×1010L.[68]The rate of star formation in the Milky Way is much higher, with the Andromeda Galaxy producing

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