This image shows an example of a bipolar planetary nebula known as NGC 6537 taken with the New Technology Telescope at ESO’s La Silla Observatory. The shape, reminiscent of a butterfly or an hourglass, was formed as a Sun-like star approached the end of its life and puffed its outer layers into the surrounding space. For bipolar nebulae, this material is funneled towards the poles of the aging star, creating the distinctive double-lobed structure.
Observations using the NTT and Hubble have found that bipolar planetary nebulae located towards the central bulge of our Milky Way appear to be strangely aligned in the sky — a surprising result given their varied and chaotic formation.
NGC 6537, which lies much closer to the Earth, was not part of the new study.
Image credit: ESO
Note: For more information, see Bizarre Alignment of Planetary Nebulae. See also Bizarre Alignment of Planetary Nebulae.