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IC 2177 and NGC 2327 - the Seagull nebulae in a wide angle
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Short object description
IC 2177 is the center of a large H-II star formation
region, mixed with blue reflection nebulae. It is an approximately circular
structure, roughly centered around the Be star HD 5336, which is also called
Seagull Nebula because of its coarse shape. In the image orientation of our
wide angle view, the seagull flies towards the lower edge of the image, whereby
the approximately circular nebula structure below the wings corresponds to the
head of the seagull.
The Seagull
Nebula is part of the Majoris OB 1 association and is located at a distance of
about 3750 light years from the solar system. IC 2177 lies along the border
between the constellations Monoceros and Canis Major.
The main components of IC 2177 are three large gas
clouds. The most prominent cloud is Sharpless 2-296, which forms the "wings".
Sh2-296 extends over about 100 light years from one wing tip to the other. It
is the radiation from newly formed young stars that gives the clouds their
fantastic colours by ionising the surrounding gas and making it
glow.
Sh2-292 (also catalogued as
NGC 2327 and Gum 1) is the name of the compact cloud that forms the prominent
head of the seagull. In the middle of Sh2-292 is the bright, large star HD
53367, 20 times as massive as our Sun with a companion of a 5 solar masses
star, orbiting HD 53367 on a strongly elliptical orbit. Sh2-292 is a mixture of
emission and blue reflection nebula (vdB 93). Most of the light is emitted by
ionized gas (red) surrounding the young stars. |
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Several smaller nebular regions are also counted as part of the
Seagull Nebula, including Sh2-297, a small, knotty extension of the tip of the
upper wing (left in the image). It is a reflection nebula (vdB 94) and
associated with the B1 star HD 53623. Further components are still Sh2-292 and
Sh2-295. Furthermore, our wide angle view of the Seagull Nebula shows a large
number of bright open star clusters, including NGC 2335, NGC 2343 and Messier
50 (right in our picture). The term Sh is an shortcut for the American
astronomer Stewart Sharpless, who created a catalogue (the Sharpless catalogue)
of over 300 such star forming regions in our Milky Way.
IC 2177 was
discovered by the Welsh amateur astronomer Isaac Roberts and described by him
as "quite bright, extremely large, irregularly round and diffuse".
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All Images and all Content are © by Franz Hofmann
+ Wolfgang Paech |