IC443

Object Description:
This is a photo of IC443, a “supernova remnant” (SNR) located in the constellation Gemini.  It is commonly known as the “Jellyfish Nebula”, and is considered to be one of the highlights of the winter astro season.

These types of objects are created by one of the most important processes in the universe - a supernova event - when a star explodes and scatters the heavier chemical elements it has synthesized during its lifetime back into space.  This material will eventually coalesce into future stars and planetary systems.

IC443 is thought to have been formed between 30,000 and 35,000 years ago, and most likely is the remains of the pulsar, G189.6+3.3.  Located about 5,000 light years away, the pulsar’s X-ray emissions excite the material of the nebula, causing the chemical components to emit light in their characteristic wavelengths.  Additionally, the expanding bubble of gas continues to plow through the interstellar medium (ISM), which are latent clouds of gas in our galaxy), and further glow is added due to this interaction.  

This nebula is comprised of hydrogen, oxygen, silicon, carbon, and iron, which were created through the nuclear fusion process during the predecessor star’s lifetime.  Photographically, it is strong in both Ha and SII light, so our narrowband filters pick this up well.

The two bright stars are Eta (Propus) and Mu Geminorum (Tejat).  Under RGB imaging, Tejat is noticeably reddish in color, illustrating its cool 3650 Kelvin degree surface and class M3 status. Lying 230 light years away (less than half the distance of Propus), Tejat is a red giant that radiates about 1540 times more energy than the Sun. The low temperature leads to a star of tremendous size, one that is actually large and close enough for an accurate measure of its angular size, 0.0135 seconds of arc. Tejat therefore has a radius 104 times that of the Sun, or 0.48 Astronomical Units, about half the size of the Earth's orbit.

Dates Taken:
  - 11/18/2006 through 3/1/2007

Equipment Used:
  - TAK FSQ
  - TMB 203 F/7
  - SBIG STL-6303
  - Paramount ME
  - FLI PDF
  - Astrodon 50mm Ha, with 6nmm bandpass

Exposures:
  - FSQ:  12x30 minute subs plus 14x5 minute subs, totaling 7 hours, 20 minutes
  - TMB: 16x30 minute subs plus 29x5 minute subs, totaling 10 hours, 25 minutes
  - Overall:  17 hours and 45 minutes

Processing:
This image is a composite or hybrid of the data from the FSQ 106-NSV F/5 (530mm) and the TMB 203 F/7 (1421mm).

Further details available at http://www.flemingastrophotography.com/ic443.html