Comet 46P/Wirtanen
Image Credit &
Copyright:
Alex Cherney
(Terrastro,
TWAN)
Explanation:
Periodic
Comet 46P/Wirtanen is now the brightest comet in the night sky,
but too faint to be seen by eye.
From dark sky sites it could just become naked-eye visible
though, as it's 5.4 year long looping orbit takes it
closest to Earth and
the Sun in mid December.
Fluorescing in sunlight,
its spherical coma is about half the
angular size of a full moon in this southern hemisphere telescopic
view from November 7.
Then the comet was about 2 light-minutes away or 35 million kilometers
from Earth-bound telescopes, so the pretty greenish coma seen here is
around 150,000 kilometers across.
That makes it about the size of Jupiter.
The stack of digital images also reveals a very faint tail
extending toward 4 o'clock with a distant background galaxy
notable at the upper left.
As a regular visitor to the inner Solar System, comet 46P/Wirtanen was
once the favored rendezvous target for ESA's comet exploring
Rosetta mission.
Source: NASA