The Jellyfish Nebula (IC 443) (Randal Healey)

The Jellyfish Nebula (IC 443)

The Jellyfish Nebula (IC 443, Sharpless 248) is a supernova remnant located in the constellation Gemini. It lies at an approximate distance of 5,000 light years from Earth and has an apparent magnitude of 12. The nebula can be found between the stars Mu and Eta Geminorum, at the foot of one of the celestial Twins.

The Jellyfish Nebula is a remnant of a supernova that occurred in the Milky Way between 3,000 and 30,000 years ago. The supernova event produced the nebula and the neutron star CXOU J061705.3+222127. The presence of the neutron star and the nebula’s location in a star forming region indicate that the remnant was created by a supernova triggered by a rapid collapse and violent explosion of a star with a mass at least 8 times that of the Sun. The neutron star is moving away from the site at about 800,000 km/h.

The nebula occupies an area of 50 arcminutes, appearing larger than the full Moon. It has a spatial diameter of about 70 light years.

IC 443 is interacting with the surrounding molecular clouds and is one of the most studied supernova remnants in the sky. The remnant has evolved in the complex environment of the molecular cloud in which the progenitor star was still embedded when it ended its life. The interaction with the cloud has affected the nebula’s morphology. In the southeastern portion of the nebula, the molecular cloud is very dense and clumpy, and the nebula’s gas appears ring-like, while the northeastern part of the nebula is interacting with a wall of neutral hydrogen, a considerably less dense environment that allows the shock to travel at a much higher velocity. The nebula’s expansion to the west is exaggerated, while the expansion to the east is experiencing a compression effect.

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