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Image: NASA/ESA/HUBBLE HERITAGE TEAM (STSCI/AURA)

More images of dying stars are throwing old theories about planetary nebulae into question. This composite taken by the Hubble Space Telescope reveals Menzel 3, or the "ant nebula," in far greater detail than ground-based instruments can. It also shows that the head and body of the "ant" are in fact a pair of fireballs coming from a central dying star. Such an explosion wouldn't normally be expected to produce this kind of symmetry--and so several new ideas about how stars die are emerging.

One way to explain Menzel 3's remarkable mirror-image extensions, scientists say, is that is has an orbiting companion star near by. Provided such a star were as close to Menzel 3 as the Earth is to the Sun, it would exert strong gravitational tidal forces capable of shaping the gas bleeding out from the dying star. It is also possible that Menzel 3 has already consumed the companion, which now orbits inside it. Another explanation looks to the magnetic fields created as a dying star spins. These field lines could twist and turn the fast flow of charged particles streaming from Menzel 3, molding them into unusual shapes.

Bruce Balick of the University of Washington and Vincent Icke of Leiden University took part of this image using the Hubble Wide Field Planetary Camera 2 in July 1997. And Raghvendra Sahai and John Trauger of the Jet Propulsion Laboratory took the rest using different filters a year later. The Hubble Heritage Team created the composite.