NGC 6302, also called the Bug Nebula, Butterfly Nebula, is a bipolar planetary nebula in the constellation Scorpius. The structure in the nebula is among the most complex ever observed in planetary nebulae.
The spectrum of NGC 6302 shows that its central star is one of the hottest stars in the galaxy, with a surface temperature in excess of 200,000 K, implying that the star from which it formed must have been very large (cf. PG 1159 star).
The central star, a white dwarf, was only recently discovered (Szyszka et al. 2009), using the upgraded Wide Field Camera 3 on board the Hubble Space Telescope.
The star has a current mass of around 0.64 solar masses. It is surrounded by a particularly dense equatorial disc composed of gas and dust.
This dense disc is postulated to have caused the star’s outflows to form a bipolar structure (Gurzadyan 1997) similar to an hour-glass. This bipolar structure shows many interesting features seen in planetary nebulae such as ionization walls, knots and sharp edges to the lobes.
Image: NASA, ESA and the Hubble SM4 ERO Team
Text: Wikipedia contributors. “NGC 6302.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 30 May. 2016. Web. 5 Jun. 2016.