C/2016 R2 (PANSTARRS) was discovered on September 7, 2016, using the Pan-STARRS telescopes. The comet has recently attracted attention from many astronomers as it approaches its closest point to the sun in May 2018. It has a very complex tail, which has been suggested to be due to a fast rotation of the nucleus. The comet was called "the blue comet" because of the rare bluish colour, which is due to the unusually abundant ionized carbon monoxide (CO+) molecules fluorescing in the sunlight.