241210 - Sh2-284 "Smiling Cat" nebula
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ASTRO:
type=emission nebula const= Monoceros IMAGE: location=EB Backyard BrtlCls=4 exposure=CMOS OSC: 88x360s (8.8h), G100 EQUIPMENT: camera=ZWO ASI2600MC-Pro optics=ES102 w 1.0x flattener, FL=714 (prime), f/7.0 filter=Optolong L-eXtreme Duo NB mount=Celestron AVX guiding=Orion 60x240mm w ASI224MC SOFTWARE: acquisition=Stellarium, NINA, PHD2 processing=PixInsight (RCAstro) (Seti Astro), Photoshop (Lumenzia) (APF-R), LrC |
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Even the Cheshire Cat in Lewis Carroll's classic tale, "Alice's Adventures in Wonderland", noted for its mischievous grin, didn't have a smile as wide as this cosmic "Smiling Cat". This distant stellar nursery appears as a grinning celestial feline with a head that is appx 150 light-years wide.
The feline-looking cloud is the brightest part of the Sh2–284 nebula and is host to a huge population of infant stars created as overly dense patches of gas and dust collapse under their own gravitational forces. The stellar nursery is located around 26,000 ly from Earth in the constellation of Monoceros.
"Monoceros" (the Unicorn), is one of 12 constellations mapped by Dutch astronomer and cartographer Petrus Plancius. Of the 12, two (2) are still recognized by the International Astronomical Union ("IAU") today. (The other is "Camelopardalis", the Giraffe). Plancius based his star-shapes on observations performed by Dutch maritime navigators. He published 6 of them, including Monoceros, on a celestial globe in Amsterdam in 1612. Monoceros was created to fill a large gap between the constellations of Orion and Hydra. There is no known mythology associated with Monoceros today.
Sh2-284 is a vast HII region of star formation. It is also listed in the catalogue of 'Lynd's Bright Nebulae' as LBN 983. Located just below the 'nose' of the cat, is a cluster of large, hot, young blue stars, dubbed the "Dolidze 25" (or Do25). Do25 is packed with a class of stars called OB stars, which are blue in color, massive, and incredibly hot. OB stars have hydrogen-burning lives of between one million and 560 million years, depending on their mass. Larger examples burn through their fuel more rapidly, while smaller ones burn their reserves more slowly. This may seem like an unimaginably long time, but compared to the predicted ten billion-year hydrogen-burning lifespan of our own Sun, which has burned roughly halfway through its anticipated life, OB stars live and die in the blink of a cosmic eye.
Yet, despite their short lifetimes, OB stars blast out an incredibly large amount of ultraviolet radiation, which has a significant impact on their environments. In the case of the Sh2–284 nebula, the Do25 star-cluster produces a large amount of radiation and powerful stellar winds. The radiation is powerful enough to ionize the hydrogen gas in the entire cloud. It is this ionization of the nebula's elemental clouds that produces the bright red and orange colors we see. In addition, powerful stellar winds from the cluster are clearing out the center of the nebula, shaping and evolving it into a distinctive hollow spherical shape. While the radiation strips electrons away from atoms of the hydrogen gas in the region thus ionizing it and causing it to glow red, the stellar winds also act like a plow pushing away gas and dust. This hollows out the region at the center of the massive cloud. Then On the flip side of this process, when these stellar winds meet more dense pockets of matter, they offer more resistance and cause the areas around them to be eroded away first. This results in the creation of "pillars" of material that can be seen radiating out from the heart of the Sh2–284 nebula.
The distance of Sh2-284 has been a subject of debate. In the 1980s, it was thought to be about 17,000 ly away, located between the Perseus Arm and the Swan Arm of the Milky Way. Then in 2007, through the study of the dynamics of galactic spiral arms, the cloud was assigned a distance of about 26,000 ly away, and therefore located in the outermost regions of the Milky Way, on the Cygnus Arm (also called the Outer Arm).
The stars within this region exhibit low metallicity, a trait common among stars in the Milky Way's outer regions. Our finding of active star formation is supported by over thirty sources of infrared radiation, and there is strong evidence of very young protostars and pre-main sequence stars, including three water (H2O) masers and three carbon monoxide (CO) masers. The 2007 study suggests that smaller and nearby nebulous regions Sh2-283, 285, and 286 are physically linked to the larger Sh2-284, thereby giving support for labeling the entire region as a cloud complex under the catalogue designation Sh2-284.
Sh2-284 is not often photographed, but is a good target for both beginner and experienced astrophotographers. While challenging due to its relatively low surface brightness and the huge population of stars in the intergalactic medium, imagers who accept the challenge are often rewarded with a very beautiful assortment of colors and sculptures that rival many similar objects.
The feline-looking cloud is the brightest part of the Sh2–284 nebula and is host to a huge population of infant stars created as overly dense patches of gas and dust collapse under their own gravitational forces. The stellar nursery is located around 26,000 ly from Earth in the constellation of Monoceros.
"Monoceros" (the Unicorn), is one of 12 constellations mapped by Dutch astronomer and cartographer Petrus Plancius. Of the 12, two (2) are still recognized by the International Astronomical Union ("IAU") today. (The other is "Camelopardalis", the Giraffe). Plancius based his star-shapes on observations performed by Dutch maritime navigators. He published 6 of them, including Monoceros, on a celestial globe in Amsterdam in 1612. Monoceros was created to fill a large gap between the constellations of Orion and Hydra. There is no known mythology associated with Monoceros today.
Sh2-284 is a vast HII region of star formation. It is also listed in the catalogue of 'Lynd's Bright Nebulae' as LBN 983. Located just below the 'nose' of the cat, is a cluster of large, hot, young blue stars, dubbed the "Dolidze 25" (or Do25). Do25 is packed with a class of stars called OB stars, which are blue in color, massive, and incredibly hot. OB stars have hydrogen-burning lives of between one million and 560 million years, depending on their mass. Larger examples burn through their fuel more rapidly, while smaller ones burn their reserves more slowly. This may seem like an unimaginably long time, but compared to the predicted ten billion-year hydrogen-burning lifespan of our own Sun, which has burned roughly halfway through its anticipated life, OB stars live and die in the blink of a cosmic eye.
Yet, despite their short lifetimes, OB stars blast out an incredibly large amount of ultraviolet radiation, which has a significant impact on their environments. In the case of the Sh2–284 nebula, the Do25 star-cluster produces a large amount of radiation and powerful stellar winds. The radiation is powerful enough to ionize the hydrogen gas in the entire cloud. It is this ionization of the nebula's elemental clouds that produces the bright red and orange colors we see. In addition, powerful stellar winds from the cluster are clearing out the center of the nebula, shaping and evolving it into a distinctive hollow spherical shape. While the radiation strips electrons away from atoms of the hydrogen gas in the region thus ionizing it and causing it to glow red, the stellar winds also act like a plow pushing away gas and dust. This hollows out the region at the center of the massive cloud. Then On the flip side of this process, when these stellar winds meet more dense pockets of matter, they offer more resistance and cause the areas around them to be eroded away first. This results in the creation of "pillars" of material that can be seen radiating out from the heart of the Sh2–284 nebula.
The distance of Sh2-284 has been a subject of debate. In the 1980s, it was thought to be about 17,000 ly away, located between the Perseus Arm and the Swan Arm of the Milky Way. Then in 2007, through the study of the dynamics of galactic spiral arms, the cloud was assigned a distance of about 26,000 ly away, and therefore located in the outermost regions of the Milky Way, on the Cygnus Arm (also called the Outer Arm).
The stars within this region exhibit low metallicity, a trait common among stars in the Milky Way's outer regions. Our finding of active star formation is supported by over thirty sources of infrared radiation, and there is strong evidence of very young protostars and pre-main sequence stars, including three water (H2O) masers and three carbon monoxide (CO) masers. The 2007 study suggests that smaller and nearby nebulous regions Sh2-283, 285, and 286 are physically linked to the larger Sh2-284, thereby giving support for labeling the entire region as a cloud complex under the catalogue designation Sh2-284.
Sh2-284 is not often photographed, but is a good target for both beginner and experienced astrophotographers. While challenging due to its relatively low surface brightness and the huge population of stars in the intergalactic medium, imagers who accept the challenge are often rewarded with a very beautiful assortment of colors and sculptures that rival many similar objects.