230522 - Cygnus Loop Cloud Complex
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click image to enlarge
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ASTRO:
type=Super Nova Remnant mag=7.0 const=Cygnus (The Swan) dist=2400 ly size=126 ly IMAGE: location=EB Driveway BrtlCls=4 moon=10% WxCr exposure=CMOS OSC; 42x90s (1.1h), Gain120 EQUIPMENT: camera=ZWO ASI2600MC-Pro optics=Nikon 70-300 kit zoom, FL=250mm, f/5.3 filter=Optolong L-eXtreme DNB mount=Celestron AVX guiding=(none) SOFTWARE: acquisition=Stellarium, APT, PHD2, processing=PixInsight, RCAstro, PhotoshopCC, LRCC |
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The Cygnus Loop, known as Sharpless 103 (or Sh2-103), is a large supernova remnant (SNR) cloud complex in the summertime constellation Cygnus (the "Swan"). Being an emission nebula measuring nearly 3° across, the Loop is a cloud of super-heated and ionized gas and dust, ...left over from a supernova star explosion that occurred many thousands of years ago, the visible parts of which represent shock-waves that are still expanding outward into space.
Cygnus Loop is a large object in the nighttime sky; covering an area large enough to fit a line of appx six (6) full Moons across its large dimension. Some parts of the Loop, known collectively as the Veil Nebula, emit light in the visible range of the electromagnetic spectrum. Scientists have also used radio, infrared, and X-ray images to detect component parts of the Loop. Analysis of these emissions indicates the presence of the elements oxygen, sulfur and hydrogen. The Cygnus Loop is a strong emitter of radio waves and X-rays. This image shows the three (3) main visual components of the Loop:
1) NGC6960 - the "Western Veil Nebula" (sometimes referred to as the "Witch's Broom", or "Cirrus" Nebula, or "Filamentary" Nebula) is pictured in the upper reaches of the image. As the westernmost NGC object in the cloud complex (first in right ascension), its number is sometimes used as the NGC identifier for the entire cloud complex.
2) "Pickering's Triangle" (also known as "Pickering's Wedge", or "Pickering's Triangular Wisp") is pictured just below and toward the left of the Western Veil. While not having received an NGC designation, this component of the complex is particularly beautiful due to its complex and kite-like appearance. This segment of relatively faint nebulosity was discovered photographically in 1904 by Williamina Fleming at Harvard Observatory, where Edward Charles Pickering was director at the time. The Triangle is brightest along the northern side of the loop, though photographs also show the nebulosity extending like the tail of a kite into the central area.
3) NGC 6992 - the "Eastern Veil Nebula" is pictured in the lower reaches of the image (...and is sometimes referred to as the "Bat" nebula due to its resemblance to the flying mammal).
Most stars that produce supernovae leave behind remnants of compact stellar material - in the form of either a neutron star or a black hole, depending on the mass of the original star. Using various measurement techniques, scientists have developed estimates of the progenitor star's mass to have been 12 to 15 times the mass of our Sun. Despite many searches, however, no compact stellar remnant has yet been found.
A noted anomaly in the X-ray spectrum shows the nebula appears near perfectly spherical. Numerous searches for a compact stellar remnant have been largely concentrated at the center of this geometry. But having found none, it is now theorized there may have been a violent ejection of the resulting neutron star. A detailed 2012 study of the region identified a possible pulsar wind nebula similar to that of M1 - the Crab Nebula, as well as a point-like source within it. Scientists today are trying to understand whether the feature is indeed a pulsar wind nebula, and if so whether it is related to the Cygnus Loop. These theories are very good, educated guesses; but, they are still unknown for certain. If it is indeed the compact stellar remnant of the supernova, and depending on the precise age and distance of the remnant, the location of this neutron star indicates it would have been ejected from the center of the Loop at a speed of roughly 1850 km/s.
The most recent investigations of the Cygnus Loop's distance using parallax measurement data of nearby stars from the Gaia Spacecraft Mission have led to the most accurate distance estimates to date. One of these stars, a 9.6 magnitude B8 star (BD+31 4224) and located near the remnant's northwestern rim shows evidence of interactions of its stellar wind with the Cygnus Loop's shock wave boundary, thereby indicating it is located actually inside the remnant. This star's Gaia estimated distance of around 730 parsecs, along with two other stars both at about 740 parsecs which exhibit spectral features indicating they must lie behind the remnant, leads to new distance of 725 parsecs, or around 2400 light-years. At that distance, the Cygnus Loop is physically some 37 parsecs (126 ly) in diameter. Using measured rates of movements (expansion) of the various parts of the cloud complex, scientists have determined it has an estimated age of around 20,000 years. That means the associated star explosion occurred appx 20,000 years ago; and we are still seeing the remnants of that explosion today.
Cygnus Loop is a large object in the nighttime sky; covering an area large enough to fit a line of appx six (6) full Moons across its large dimension. Some parts of the Loop, known collectively as the Veil Nebula, emit light in the visible range of the electromagnetic spectrum. Scientists have also used radio, infrared, and X-ray images to detect component parts of the Loop. Analysis of these emissions indicates the presence of the elements oxygen, sulfur and hydrogen. The Cygnus Loop is a strong emitter of radio waves and X-rays. This image shows the three (3) main visual components of the Loop:
1) NGC6960 - the "Western Veil Nebula" (sometimes referred to as the "Witch's Broom", or "Cirrus" Nebula, or "Filamentary" Nebula) is pictured in the upper reaches of the image. As the westernmost NGC object in the cloud complex (first in right ascension), its number is sometimes used as the NGC identifier for the entire cloud complex.
2) "Pickering's Triangle" (also known as "Pickering's Wedge", or "Pickering's Triangular Wisp") is pictured just below and toward the left of the Western Veil. While not having received an NGC designation, this component of the complex is particularly beautiful due to its complex and kite-like appearance. This segment of relatively faint nebulosity was discovered photographically in 1904 by Williamina Fleming at Harvard Observatory, where Edward Charles Pickering was director at the time. The Triangle is brightest along the northern side of the loop, though photographs also show the nebulosity extending like the tail of a kite into the central area.
3) NGC 6992 - the "Eastern Veil Nebula" is pictured in the lower reaches of the image (...and is sometimes referred to as the "Bat" nebula due to its resemblance to the flying mammal).
Most stars that produce supernovae leave behind remnants of compact stellar material - in the form of either a neutron star or a black hole, depending on the mass of the original star. Using various measurement techniques, scientists have developed estimates of the progenitor star's mass to have been 12 to 15 times the mass of our Sun. Despite many searches, however, no compact stellar remnant has yet been found.
A noted anomaly in the X-ray spectrum shows the nebula appears near perfectly spherical. Numerous searches for a compact stellar remnant have been largely concentrated at the center of this geometry. But having found none, it is now theorized there may have been a violent ejection of the resulting neutron star. A detailed 2012 study of the region identified a possible pulsar wind nebula similar to that of M1 - the Crab Nebula, as well as a point-like source within it. Scientists today are trying to understand whether the feature is indeed a pulsar wind nebula, and if so whether it is related to the Cygnus Loop. These theories are very good, educated guesses; but, they are still unknown for certain. If it is indeed the compact stellar remnant of the supernova, and depending on the precise age and distance of the remnant, the location of this neutron star indicates it would have been ejected from the center of the Loop at a speed of roughly 1850 km/s.
The most recent investigations of the Cygnus Loop's distance using parallax measurement data of nearby stars from the Gaia Spacecraft Mission have led to the most accurate distance estimates to date. One of these stars, a 9.6 magnitude B8 star (BD+31 4224) and located near the remnant's northwestern rim shows evidence of interactions of its stellar wind with the Cygnus Loop's shock wave boundary, thereby indicating it is located actually inside the remnant. This star's Gaia estimated distance of around 730 parsecs, along with two other stars both at about 740 parsecs which exhibit spectral features indicating they must lie behind the remnant, leads to new distance of 725 parsecs, or around 2400 light-years. At that distance, the Cygnus Loop is physically some 37 parsecs (126 ly) in diameter. Using measured rates of movements (expansion) of the various parts of the cloud complex, scientists have determined it has an estimated age of around 20,000 years. That means the associated star explosion occurred appx 20,000 years ago; and we are still seeing the remnants of that explosion today.