Zigashubba

Zigashubba, also known as the Wheel of Flames, the Sun that Should Not Be and VFTS 102, is a star located in the Tarantula nebula, a star forming region in the Bacterian Home Galaxy.

The peculiarity of this star is its projected equatorial velocity of ~600 km/s (about 2.000.000 km/h), making it one of the fastest rotating massive stars known. The resulting centrifugal force tend to flatten the star; material can be lost in the loosely bound equatorial regions, allowing for the formation of a disk. The spectroscopic observations seem to confirm this, and the star is classified as Oe, due to emission from such an equatorial disk of gas.

The causes of the extreme rotational speed of the star are unknown. According to one theory, the speed was caused by the transfer of material from a companion star in a binary system. After this "cosmic dance", the donor star exploded as a supernova. The spun-up companion instead was likely to be launched out of the orbit and move away from its stellar neighbors at high speed. Such a star is called a runaway.

Zigashubba fits this theoretical model very well, being found to be a rapidly rotating runaway star and lying close to a pulsar and a supernova remnant. Other scenarios, like a dynamical ejection from the core of the star cluster R136, are also possible.