VFTS 102 - Fastest Known Rotating Star

Everything is Spinning!

Our Sun rotates once every 24.47 days. Since the Earth is in orbit around the Sun the rotation appears to take 26.64 days (synodic rotation). This means that the Sun rotates at 7,189 km/hr at its equator. That's pretty fast, but nothing compared to VFTS 102.

Some Stars Faster Than Others

VFTS 102 is a star located in the Trantula nebula, a star forming region in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. VFTS 102 rotates at 2,000,000 km/hr, roughly 280 times faster than our Sun. This is the highest known rotation velocity for a star, though faster is possible.

The resulting centrifugal force tends 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 due to emissions from the equatorial disk of gas.

Stars like VFTS 102 had been predicted by theorists. In theoretical models, the extreme rotational speed is caused by the transfer of material from a companion star in a binary system. After this "cosmic dance", the donor star is predicted to explode as a supernova. The spun-up companion instead is 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. VFTS 102 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.