An Iris Rising from the Dust
(Click on images to enlarge)NGC7023, Iris Nebula
We usually think of space as a place filled with island universes that we know as galaxies. Each galaxy being comprised of literally hundreds of billions of stars. We may assume that between all of these stars and galaxies lies empty space. This couldn’t be further from the truth. Space is home to a sea of molecular clouds and interstellar dust, interspersed only occasionally by a nuclear furnace we call a star. It is estimated that 1000 tons of dust rains down on the earth every year. This dust has its origins in broken up asteroids, comet tails and spent stars whose wake our earth is passing through on its journey through space. Larger stars end their life cycle in a cataclysmic explosion that accelerates dust and elements throughout the cosmos. The shock waves from such explosions also act as the catalyst to begin new star formation in already existing dust filled molecular clouds. Such clouds represent the more dense areas of the interstellar medium. Those with a core size of approximately 10,000 AU, (AU= Astronomical Unit= distance between the Sun and the Earth= 93 million miles) are relatively unstable, and only a small increase in density can lead to “Jeans Instability”. When this density level occurs, a blast wave as described above will initiate a collapse event where the cloud will begin to fall into itself as gravity has it’s way…and a stars creation has begun.
In the image above, such a process has occurred. A radiant and reflective dust filled molecular cloud, NGC7023 surrounds a relatively young, pre-main sequence host star, HD 200775. HD200775 is a 10 solar mass Herbig Be star. The strong solar winds emitted by this star form the unique Iris pattern, for which this nebula is named. The winds work to push back the dusty, molecular cloud from which the star was formed. Most of the color near the star is blue, as the light reflects off innumerable particles of dust. Hues of red and purple are also seen as hydrogen and other elements are ionized by the radiation from the star. Some areas of dust surrounding the star are completely black and opaque to the naked eye. Infrared surveys however reveal similar star formation occurring inside the body of these black Iris petals as well.
Image Acquisition info:
Location: Star Lodge Observatory
Date: May, 2008
Scope: Planewave, CDK 12.5
Camera: SBIG STL 11000
LRGB 310:120:120:120 (11 hrs of data)
We usually think of space as a place filled with island universes that we know as galaxies. Each galaxy being comprised of literally hundreds of billions of stars. We may assume that between all of these stars and galaxies lies empty space. This couldn’t be further from the truth. Space is home to a sea of molecular clouds and interstellar dust, interspersed only occasionally by a nuclear furnace we call a star. It is estimated that 1000 tons of dust rains down on the earth every year. This dust has its origins in broken up asteroids, comet tails and spent stars whose wake our earth is passing through on its journey through space. Larger stars end their life cycle in a cataclysmic explosion that accelerates dust and elements throughout the cosmos. The shock waves from such explosions also act as the catalyst to begin new star formation in already existing dust filled molecular clouds. Such clouds represent the more dense areas of the interstellar medium. Those with a core size of approximately 10,000 AU, (AU= Astronomical Unit= distance between the Sun and the Earth= 93 million miles) are relatively unstable, and only a small increase in density can lead to “Jeans Instability”. When this density level occurs, a blast wave as described above will initiate a collapse event where the cloud will begin to fall into itself as gravity has it’s way…and a stars creation has begun.
In the image above, such a process has occurred. A radiant and reflective dust filled molecular cloud, NGC7023 surrounds a relatively young, pre-main sequence host star, HD 200775. HD200775 is a 10 solar mass Herbig Be star. The strong solar winds emitted by this star form the unique Iris pattern, for which this nebula is named. The winds work to push back the dusty, molecular cloud from which the star was formed. Most of the color near the star is blue, as the light reflects off innumerable particles of dust. Hues of red and purple are also seen as hydrogen and other elements are ionized by the radiation from the star. Some areas of dust surrounding the star are completely black and opaque to the naked eye. Infrared surveys however reveal similar star formation occurring inside the body of these black Iris petals as well.
Image Acquisition info:
Location: Star Lodge Observatory
Date: May, 2008
Scope: Planewave, CDK 12.5
Camera: SBIG STL 11000
LRGB 310:120:120:120 (11 hrs of data)
posted by Pictoris ab Lumen at 2:24 PM
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