IC443 and Sh2-249 in Gemini, The Monkey's
Head (NGC2174,
NGC2175, IC2159) in Orion
[from Wikipedia:
IC 443 (bright "jellyfish" shaped nebula near the top) is a Super Nova
Remnant (SNR) and has an angular diameter of almost 2 full moons. At
the estimated distance of 5,000 ly
from Earth, it corresponds to a physical size of roughly 70 light years.
The remnant's age is still uncertain. There is some agreement that
the supernova happened between 3,000 and 30,000 years ago. Near
the apex of the nebula is a neutron star, relic of a SN explosion. The
location in a star forming region and the presence of a neutron star
favor a Type II supernova, the ultimate fate of a massive star, as the
progenitor explosion.
The remnant is evolving in a rich and complex environment, which
strongly affects its morphology. Multi-wavelength observations show the
presence of sharp density gradients and different cloud geometries in
the surroundings of IC 443. Massive stars are known to be short lived
(roughly 30 million years), ending their life when they are still
embedded within the progenitor cloud. The more massive stars (O-type)
probably clear the circum-stellar environment by powerful stellar winds
or photoionizing radiation. Early B-type stars, with a typical mass
between 8 and 12 solar masses, are not capable of this, and they likely
interact with the primordial molecular cloud when they explode. Thus,
it is not surprising that the SNR IC 443, which is thought to be the
aftermath of a stellar explosion, evolved in such a complex
environment. For instance, an appreciable fraction of supernova
remnants lies close to dense molecular clouds and most of
them show clear signs of interaction with the adjacent cloud.
Sh2-249 is the fainter cloud of gas in the upper left corner and IC443
is interacting with it as IC443 expands.
The bright nebula in the lower right is called The Monkey's Head
Nebula! It is over the boundary into the constellation Orion. Can you
see the monkey's head? I see it in profile facing to the right. There
seem to be a number of catalog numbers associated with it: IC2159 plus
NGC2174 and NGC2175 (which is actually the catalog number for the Open
Cluster embedded in the nebula). Monkey's Head seems easier!
Apogee U16M camera w Astrodon Gen II filters
Takahashi FSQ Refractor w Robofocus
21 x 10 min for H-Alpha
Paramount ME guided w ST-402 and eFinder
Image acquisition in CCDSoft5
Conditions were less than ideal and I was battling a lot of thin cloud
coming and going over the night. Hence the halos around the bright
stars.
Calibration, Alignment and Sigma Reject combine in Maxim
Levels, Curves in
PS CS4
Click on the image to see it 2x in size or to have your browser resize
it for your screen.
Captured Nov 29th
2010
Flesherton, Ontario
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