The farthest comet showing activity is found

Comets are ice blocks which are concealed in far space, and become noticeable only at approach to the Sun when radiation from a star forces a comet to form "tail" - to whom. However the Hubble telescope managed to find a comet with the arising coma at very long distance – usually they noticeable become much closer. An indistinct cloud of dust more than 100 thousand km in the diameter the comet began to form at distance about 2 billion km from the Sun (that is further, than an orbit of Saturn). 

The comet has received the name C/2017 K2 PANSTARRS (K2). Possibly, it is the first entrance of a comet to a zone close to the Sun as the cloud surrounding her doesn't consist of water as at other comets which show activity at closer distance. It is sublimation more volatiles which had to "be blown off" from it at the previous ways to the Sun if they were. Now from her oxygen, nitrogen, carbon oxides sublimate. About 18 km in the diameter are a comet nucleus. And work with archives has shown that this comet was accidentally noticed in 2013, but then haven't given attention to this object. That is she showed activity even behind the Neptune's orbit.

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