Distant Active Comet C/2017 K2

Hubble Uncovers the Farthest Active Inbound Comet Yet Seen

This Hubble Space Telescope image shows a fuzzy cloud of dust, called a coma, surrounding the comet C/2017 K2 PANSTARRS (K2), the farthest active comet ever observed entering the solar system.

Hubble snapped images of K2 when the frozen visitor was 1.5 billion miles from the Sun, just beyond Saturn's orbit. Even at that remote distance, sunlight is warming the frigid comet, producing an 80,000-mile-wide coma that envelops a tiny, solid nucleus.

K2 has been traveling for millions of years from its home in the Oort Cloud, a spherical region at the edge of our solar system. This frigid area contains hundreds of billions of comets, the icy leftovers from the formation of the solar system 4.6 billion years ago.

The image was taken in June 2017 by Hubble's Wide Field Camera 3.

About the colours

These images represent several exposures acquired by the WFC3/UVIS instrument through the F350LP filter on the Hubble Space Telescope. Color has been applied to the grayscale (black&white) images; the brightness maps to different color values.

About the data

Data were provided by the HST proposals 14939 (D. Jewett, P.I.).