Hubble's visible-light image of the disk of Mira reveals it has an odd, asymmetrical shape resembling a football. This may be tied to dramatic changes occurring during its expansion-contraction cycles, or to the presence of unresolved spots on its surface. Hubble measurements show the red giant star is 700 times larger than our Sun.
Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) and NASA
<a rel="nofollow" class="external free" href="http://hubblesite.org/image/499/news_release/1997-26">http://hubblesite.org/image/499/news_release/1997-26</a>