what is its orbit?
It passes just 0.1 AU from Earth.
Comet Hyakutake
pass just 0.1 AU from Earth 
what is comet hyakutake? It is a comet. who discovered it? Yuji Hyakutake
wiki:1220034
Comet Hyakutake [SEP] Orbit
When the first calculations of the comet's orbit were made, scientists realized that it was going to pass just 0.1 AU from Earth on 25 March. Only four comets in the previous century had passed closer. Comet Hale–Bopp was already being discussed as a possible "great comet"; the astronomical community eventually realised that Hyakutake might also become spectacular because of its close approach. Moreover, Comet Hyakutake's orbit meant that it had last been to the inner Solar System approximately 17,000 years earlier. Because it had probably passed close to the Sun several times before, the approach in 1996 would not be a maiden arrival from the Oort cloud, a place where comets with orbital periods of millions of years come from.