Planetary Nebula Mz3: The Ant Nebula . ... Hubble Heritage Team , ESA , NASA Explanation: Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant -shaped nebula that is distinctly not round? ... One possible answer is that Mz3 is hiding a second, dimmer star that orbits close in to the bright star. ... NASA Web Site Statements, Warnings, and Disclaimers . ...