The story
From Hubble (“surname”) + star. From having the variable nature of this star being discovered by Edwin Hubble. From this being a very important star in the history of astronomy, and the discovery made using it by Hubble, that the Universe contains galaxies beyond the Milky Way, and is much larger than just the size of the Milky Way Galaxy.
Etymology from Wiktionary, CC BY-SA 4.0.