IC 443 ( Sh2-248, Jellyfish Nebula) in Gemini

© Velimir Popov & Emil Ivanov 2020
Size: 1800 px
IC 443 is a supernova remnant located in the constellation Gemini. It is believed that it originated from a supernova that exploded between 3000 and 30,000 years ago, and that the nucleus of the progenitor star responsible for this event formed the neutron star CXOU J061705.3 + 222127. It is a very studied object because of its interaction with other molecular clouds. IC 443 has an angular diameter of 50 arc minutes, which at a distance of 5,000 light years equals a real size of about 70 light years. The nebula, both in the visible and in the radio waves, has a shell shape, consisting of two halves with different radius and center; a third cloud shell, initially attributed to IC 443, is now recognized as an older supernova remnant, perhaps 100,000 years old, called G189.6 + 3.3 . The age of the object remains uncertain; there is some agreement that the event that created the nebula occurred between 3000 and 30,000 years ago. Through the observations conducted with the Chandra X-ray Observatory and with the XMM-Newton the pulsar was identified near the southern ring. IC 443 is located in the direction of the galactic anticenter (l = 189.1 °), near the galactic plane (b = + 3.0 °). Many objects are found in this area of ​​sky, such as the HII Sh2-249 region, several young stars belonging to the Gem OB1 association and the remains of older supernovae (G189.6 + 3.3). The nebula evolves in a rich and complex environment, which strongly influences its morphology; multi-wavelength observations conducted in this area of ​​sky show the presence of shape gradients and different cloud geometries. Massive stars are known to have a relatively short life (about 30 million years) and to end their lives when they are still within the progenitor cloud; the most massive stars (class O stars) illuminate the surrounding environment with their powerful stellar wind. Type B stars, with a typical mass between 8 and 12 solar masses, are unable to sweep the surrounding environment with their radiation and when they explode as supernovae they interact with the surrounding environment. So it is not surprising that IC 443 is surrounded by other large nebulous complexes; in fact, a good part of the known supernova remnants are found in the vicinity of these nebulous complexes (about 50 of the 265 remnants reported in the Green Catalog [5]), and many of these (about 60%) show clear signs of interaction with a surrounding cloud. Optical and X-ray images are characterized by a dark line, which crosses IC 443 from north-west to south-east; the emission from quiescent molecular gas has been observed in the same direction, and is probably due to the presence of a giant molecular cloud, placed between us and the rest of the supernova..

Image details:


Center of field RA 06:16:44
Center of field DE +22:29:37 (deg:m:s)
Size 1.35 x 1 (deg)
Pixel scale: 2.7 (arcsec/pixel)
Orientation: Up is 9.2 degrees E of N
Charts and image details obtained from Astrometry.net
Optic(s): 12" ASA Astrograph at F/6.8 and F/3.6
Mount: ASA DDM85 Standard
Camera: SBIG STL 11000 M
Filters: Luminance, Red, Green, Blue, Astronomik filters; Ha, SII, OIII Baader filters
Dates/Times: Nov-Dec. 2010
Location: IRIDA Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exp. Details: ;R:6x10 min, G:6x10 min, B:6x10 min;Ha:16x30 min;SII:16x30 min;OIII:16x30 min; Bin 1 Total exp.time: 1620 min. (27 hrs)
More details: Dark and flat frames reduction
Processing: PixInsight / PS
Copyright: Velimir Popov and Emil Ivanov 2020. All Rights Reserved
e-mail: info@irida-observatory.org
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