NGC 6302

NGC 6302, also known as the bug nebula or the butterfly nebula, is a planetary nebula in the constellation of Scorpius. It is about 3.4 thousand light-years away from Earth.
The spectrum of NGC 6302 shows that its central star is one of the hottest stars in the galaxy. Its surface temperature is over 250,000 degrees Celsius. This means the star from which it formed must have been very large.
The central star, a white dwarf, was only recently discovered by the upgraded Wide Field Camera 3 on board the Hubble Space Telescope. 
The star now has a mass of about 0.64 solar masses. It is surrounded by a dense disc of gas and dust. This dense disc may have caused the star's outflows to form a bipolar structure like 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.