It can't be a galaxy 490LY away - the Milky Way is 100,000LY across or so - the nearest galaxy to ours (that isn't a satellite of ours either) according to wikipedia is Leo II at 680,000LY away.
It must have been a star - I'm sure there would be hundreds of stars (if not more) within the Milky Way that harbour hospitable or potentially hospitable planets....
http://en.wikipedia.org/wiki/List_of_nearest_galaxies