IC 443 (also known as the
Jellyfish Nebula and
Sharpless 248 (
Sh2-248)) is a galactic
supernova remnant (SNR) in the constellation
Gemini. On the plane of the sky, it is located near the star
Eta Geminorum. Its distance is roughly 5,000
light years from Earth.IC 443 may be the remains of a
supernova that occurred 30,000 - 35,000 years ago. The same supernova event likely created the
neutron starCXOU J061705.3+222127, the collapsed remnant of the stellar core. IC 443 is one of the best-studied cases of supernova remnants interacting with surrounding molecular clouds.
C 443 is an extended source, having an angular diameter of 50
arcmin (by comparison, the full moon is 30 arcmin across). At the estimated distance of 5,000
ly (1,500
parsec) from Earth, it corresponds to a physical size of roughly 70 light years (20 parsec).The SNR optical and radio morphology is shell-like (e.g. a prototypical shell-like SNR is
SN 1006), consisting of two connected sub-shells with different centers and radii. A third, larger sub-shell—initially attributed to IC 443—is now recognized as a different and older (100,000 years) SNR, called G189.6+3.3.
Notably, IC 443 X-ray morphology is centrally peaked and a very soft X-ray shell is barely visible. Unlike plerion remnants, e.g. the
Crab Nebula, the inner X-ray emission is not dominated by the central
pulsar wind nebula. It has indeed a thermal origin. IC 443 shows very similar features to the class of mixed morphology
[4] SNRs. Both optical and X-ray emission are heavily absorbed by a giant molecular cloud in the foreground, crossing the whole remnant body from northwest to southeast.
SQM16,84 Miami city ,FL USA
.
Comments