240109 - M1 "Crab" nebula
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click image to enlarge
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ASTRO:
type=Super Nova Remnant mag=8.4 const=Taurus dist=6500 ly size=13 ly IMAGE: location=EB Driveway BrtlCls=4 exposure=CMOS OSC; 73x360s (7.3h) EQUIPMENT: camera=ZWP ASSI2600MC-Pro optics=ES102 w1.7x (Hyperion 24mmEP) afocal proj., FL(eff.)=1238mm, f/12.0 filter=Optolong L-eXtreme Duo NB mount=Celestron AVX guiding=Orion 60x240mm, ZWO ASi224MC SOFTWARE: acquisition=Stellarium, APT, PHD2, processing=PixInsight, RCAstro, PhotoshopCC, Lumenzia, APF-R, LrC |
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One of the most interesting objects in the night sky, the Crab Nebula is cataloged as M1, the first object on Charles Messier's famous list of astronomical objects that are NOT comets. In fact, the Crab is now known to be a supernova remnant, expanding debris from a massive star's death explosion, witnessed on planet Earth and recorded by medieval astronomers in 1054 AD. Hosting one of the most exotic objects known to modern astronomers, the nebula encloses the Crab Pulsar, itself containing a neutron star that is spinning 30 times per second. The pulsar is visible as the bright area in the nebula's center. Like a cosmic gyrating dynamo, this spinning collapsed remnant of the stellar core powers the Crab's light emissions. Spanning about 13 light-years across, the Crab Nebula is located appx 6,500 light-years away in the constellation Taurus.
Our modern understanding that the Crab Nebula was created by a supernova, traces to the year 1921, when American astronomer Carl Otto Lampland announced he had seen changes in the nebula's structure. This eventually led to the conclusion that the creation of the Crab Nebula corresponds to the bright object labeled SN-1054, a supernova recorded by medieval astronomers in the year 1054 AD.
The nebula was first identified in 1731 by early English astronomer John Bevis. It was then independently rediscovered 27 years later (in 1758) by Charles Messier as he was searching for the return of Halley's comet. Messier catalogued it as the first entry in his famous catalogue of non-comet-like objects; that because of their behavior, were deemed NOT to be comets. Prompting Messier's record-keeping was the reexamination by French mathematician, astronomer, and geophysicist Alexis Clairaut a year earlier in 1757, of calculations by Edmund Halley predicting the return of Halley's Comet in late 1758. Clairaut more precisely adjusted Halley's calculations for the exact time of the comet's return by including considerations for the effect to its trajectory caused by the planet Jupiter, which resulted in his finding that the comet should appear in the constellation of Taurus. It was through his searching in vain for the comet that Charles Messier found the Crab Nebula, which he at first thought in-fact to be Halley's comet. ...But after close observation over a period of days, he determined the object was not moving across the sky and concluded that the object was not a comet. He then realized the usefulness of compiling a catalogue of celestial objects having a cloudy nature, but fixed in the sky, to avoid incorrectly cataloguing them as comets. This realization led him to compile his now famous "Messier catalogue" of 110 cloud-like astronomical objects.
William Parsons, 3rd Earl of Rosse observed the nebula from Birr Castle in 1844 using a 36-inch (0.9 m) telescope and referred to it as the "Crab Nebula" because a drawing he made of it looked like a crab. He observed it again 4 years later, in 1848, using a 72-inch (1.8 m) telescope but could not confirm the supposed resemblance. The name stuck, nonetheless. Most astronomers today surmise that the nebula probably changed in appearance during that 4-year span.
The Crab Nebula was the first astronomical object recognized as being connected to a supernova explosion. In the early twentieth century, analysis of early photographs of the nebula taken several years apart revealed that it was indeed expanding. Using the rate of expansion and tracing the expansion back through time indicated the nebula must have become visible on Earth about 900 years before. An ensuing search of historical records revealed that a new star, bright enough to be seen in the daytime, had been recorded in the same part of the sky by Chinese astronomers on July 4, 1054.
Then in 1928, renowned astrophysicist Edwin Hubble proposed associating the cloud with the historic star of 1054, an idea that was very controversial until the nature of supernovae was understood. Through his studies specifically looking at the internal motions of astronomical objects, particularly the Crab Nebula, American astronomer Nicholas Mayall proved in 1936 that the star of 1054 was in fact the supernova whose explosion produced the Crab Nebula. This revelation led immediately to the search for other historical supernovae: To date, seven (7) other historical sightings have been found by comparing modern observations of supernova remnants with historical astronomical documents of past centuries.
Given its great distance, the "daytime star" observed by the Chinese could only have been a supernova - a massive, exploding star, having exhausted its supply of energy from nuclear fusion and collapsing in on itself. Continued study of historical records has found the supernova that created the Crab Nebula probably appeared in April or early May, rising to its maximum brightness by July of between apparent magnitude −7 and −4.5 (...even brighter than Venus' −4.2 and everything else in the night sky except the Moon). The supernova was visible to the naked unaided eye for about two years after its first observation.
In the more recent 1960s, because of the prediction and discovery of pulsars, the Crab Nebula again became a major center of interest to the scientific astronomical community. It was in 1968 that Franco Pacini, an Italian astrophysicist and professor at the University of Florence, predicted the existence of the Crab Pulsar. Prof. Pacini's analysis explained for the first time the brightness of the nebula cloud. The actual remnant neutron star itself was observed shortly afterward in that same year. The inner part of the Crab Nebula is dominated by a pulsar wind nebula enveloping a pulsar commonly called the Crab Pulsar.
The nebula is still expanding at a rate of appx 1,500 kilometers per second. Over the past decade, its expansion has been documented by amatuer astronomer Detlef Hartmann in a stunning time-lapse movie. In each year from 2008 to 2022 (15 years total duration), Hartmann produced an image using the same telescope and camera from a remote observatory in the country of Austria and has stitched the ensuing images together to document the resulting motion. The sharp, processed frames even reveal the dynamic energetic emission surrounding the rapidly spinning pulsar at the center.
The discovery of the Crab Pulsar, and the knowledge of its exact age (almost to the day) allows for the verification of basic physical properties of these objects, such as characteristic age and spin-down luminosity, the orders of magnitude involved (notably the strength of the magnetic field), along with various aspects related to the dynamics of the remnant neutron star. No other historical supernova has yet been discovered to have created a pulsar whose precise age is known for certain. The role of the Crab Nebula supernova is crucial to the astronomical scientific community and its scientific understanding of supernova remnants.
Our modern understanding that the Crab Nebula was created by a supernova, traces to the year 1921, when American astronomer Carl Otto Lampland announced he had seen changes in the nebula's structure. This eventually led to the conclusion that the creation of the Crab Nebula corresponds to the bright object labeled SN-1054, a supernova recorded by medieval astronomers in the year 1054 AD.
The nebula was first identified in 1731 by early English astronomer John Bevis. It was then independently rediscovered 27 years later (in 1758) by Charles Messier as he was searching for the return of Halley's comet. Messier catalogued it as the first entry in his famous catalogue of non-comet-like objects; that because of their behavior, were deemed NOT to be comets. Prompting Messier's record-keeping was the reexamination by French mathematician, astronomer, and geophysicist Alexis Clairaut a year earlier in 1757, of calculations by Edmund Halley predicting the return of Halley's Comet in late 1758. Clairaut more precisely adjusted Halley's calculations for the exact time of the comet's return by including considerations for the effect to its trajectory caused by the planet Jupiter, which resulted in his finding that the comet should appear in the constellation of Taurus. It was through his searching in vain for the comet that Charles Messier found the Crab Nebula, which he at first thought in-fact to be Halley's comet. ...But after close observation over a period of days, he determined the object was not moving across the sky and concluded that the object was not a comet. He then realized the usefulness of compiling a catalogue of celestial objects having a cloudy nature, but fixed in the sky, to avoid incorrectly cataloguing them as comets. This realization led him to compile his now famous "Messier catalogue" of 110 cloud-like astronomical objects.
William Parsons, 3rd Earl of Rosse observed the nebula from Birr Castle in 1844 using a 36-inch (0.9 m) telescope and referred to it as the "Crab Nebula" because a drawing he made of it looked like a crab. He observed it again 4 years later, in 1848, using a 72-inch (1.8 m) telescope but could not confirm the supposed resemblance. The name stuck, nonetheless. Most astronomers today surmise that the nebula probably changed in appearance during that 4-year span.
The Crab Nebula was the first astronomical object recognized as being connected to a supernova explosion. In the early twentieth century, analysis of early photographs of the nebula taken several years apart revealed that it was indeed expanding. Using the rate of expansion and tracing the expansion back through time indicated the nebula must have become visible on Earth about 900 years before. An ensuing search of historical records revealed that a new star, bright enough to be seen in the daytime, had been recorded in the same part of the sky by Chinese astronomers on July 4, 1054.
Then in 1928, renowned astrophysicist Edwin Hubble proposed associating the cloud with the historic star of 1054, an idea that was very controversial until the nature of supernovae was understood. Through his studies specifically looking at the internal motions of astronomical objects, particularly the Crab Nebula, American astronomer Nicholas Mayall proved in 1936 that the star of 1054 was in fact the supernova whose explosion produced the Crab Nebula. This revelation led immediately to the search for other historical supernovae: To date, seven (7) other historical sightings have been found by comparing modern observations of supernova remnants with historical astronomical documents of past centuries.
Given its great distance, the "daytime star" observed by the Chinese could only have been a supernova - a massive, exploding star, having exhausted its supply of energy from nuclear fusion and collapsing in on itself. Continued study of historical records has found the supernova that created the Crab Nebula probably appeared in April or early May, rising to its maximum brightness by July of between apparent magnitude −7 and −4.5 (...even brighter than Venus' −4.2 and everything else in the night sky except the Moon). The supernova was visible to the naked unaided eye for about two years after its first observation.
In the more recent 1960s, because of the prediction and discovery of pulsars, the Crab Nebula again became a major center of interest to the scientific astronomical community. It was in 1968 that Franco Pacini, an Italian astrophysicist and professor at the University of Florence, predicted the existence of the Crab Pulsar. Prof. Pacini's analysis explained for the first time the brightness of the nebula cloud. The actual remnant neutron star itself was observed shortly afterward in that same year. The inner part of the Crab Nebula is dominated by a pulsar wind nebula enveloping a pulsar commonly called the Crab Pulsar.
The nebula is still expanding at a rate of appx 1,500 kilometers per second. Over the past decade, its expansion has been documented by amatuer astronomer Detlef Hartmann in a stunning time-lapse movie. In each year from 2008 to 2022 (15 years total duration), Hartmann produced an image using the same telescope and camera from a remote observatory in the country of Austria and has stitched the ensuing images together to document the resulting motion. The sharp, processed frames even reveal the dynamic energetic emission surrounding the rapidly spinning pulsar at the center.
The discovery of the Crab Pulsar, and the knowledge of its exact age (almost to the day) allows for the verification of basic physical properties of these objects, such as characteristic age and spin-down luminosity, the orders of magnitude involved (notably the strength of the magnetic field), along with various aspects related to the dynamics of the remnant neutron star. No other historical supernova has yet been discovered to have created a pulsar whose precise age is known for certain. The role of the Crab Nebula supernova is crucial to the astronomical scientific community and its scientific understanding of supernova remnants.