Ever heard of something called crab nebula? If no, then you came to the right place. Today we present you crab nebula facts that you would wish you knew them earlier.
There are around 3,000 nebulae in our Milky Way galaxy alone. Out of the 3,000 nebulae, few of them are famous such as pipe nebula, snake nebula, prawn nebula, dark horse, etc. Crab nebula is one of them. So, without further ado, let’s begin our crab nebula facts.
History of the Crab Nebula
Chinese astronomers recorded an explosion of a supernova on 4 July 1054 CE.
The bright light of the explosion was visible for straight 23 days. It shined six times brighter than Venus!
The ones who were good with night-sky observations observed this bright light for 653 days – approximately 2 years that too with their naked eye.
This nebula was observed later by John Bevis, an English astronomer in the year 1731.
This supernova’s remnant is the crab nebula. This nebula is also known as M1, Taurus A, and NGC 1952.
In 1757, Alexis Clairaut predicted the return of Halley’s comet in 1758 after reexamining Edmund Halley’s calculations.
Alexis Clairaut, Nicole-Reine Lepaute, and Jérôme Lalande further calculated and concluded that the comet would come in the constellation of Taurus.
At the same time, a French astronomer, Charles Messier again discovered the crab nebula in 1758. He earlier thought that it was Halley’s comet.
However, after observing that the celestial object didn’t move, he concluded that it was not Halley’s comet.
William Herschel has observed crab nebula several times from 1783 to 1809. He also discovered crab nebula independently.
After observing it for several times and closely, he concluded that it is made up of many stars.
The name of the crab nebula was given by the 3rd Earl of Rosse, William Parsons. He observed this object in 1844 at Birr Castle.
He observed this nebula with the help of a 36-inch telescope and he observed that the nebula looked somewhat like a crab.
He observed it again in 1848 with a bigger telescope (72-inch) but this time he couldn’t confirm the shape of the nebula.
However, the name “crab nebula” remained as is.
The crab nebula is part of the Taurus constellation and hence the name Taurus A.
Vesto Slipher studied crab nebula in his spectroscopy study in 1913. Further studies on crab nebula revealed that the nebula was expanding.
It was also revealed that crab nebula was visible on Earth from some 900 years back.
In 1921, Carl Lampland discovered some structural changes in crab nebula. In the same year, John Charles Duncan demonstrated that crab nebula was expanding.
In 1921 again, Knut Lundmark noted the proximity of crab nebula to guest star of 1054.
In 1928, Edmund Halley proposed that the celestial object (which was crab nebula) be associated with the star of 1054.
However, this proposal was controversial until the supernovae’s nature was understood.
Nicholas Mayall indicated that the star of 1054 was the supernova which exploded and eventually produced the crab nebula.
This started the search for historical supernovae. Seven historical sightings were found by comparing historical astronomical documents with modern observations of the remnants of supernovae.
Studies conclude that the explosion of the supernova which produced crab nebula appeared in early May or April. It reached its maximum brightness in July.
The explosion of the supernova was so bright that it blinded everything in the night except the Moon.
Crab nebula is the first celestial object which was connected to the explosion of a supernova.
In the 1960s, crab nebula was again the center of attention with the discovery of pulsars.
Franco Pacini predicted that crab pulsar exists for the first time.
The star was also discovered in 1968.
The whole episode of crab nebula and its supernova led to the understanding a lot about supernovae.
Crab nebula also has pulsar wind nebula in its inner part in the form of a shell surrounding crab pulsar.
Crab nebula emitting gamma rays in excess of 100 TeV was recorded in 2019. It became the first identified source to emit gamma rays in excess of 100 TeV.
Conditions of the M1 Nebula
In this segment of crab nebula facts, we will talk about various physical conditions of the crab nebula like mass, distance, shape, etc.
Crab nebula consists of an oval-shaped mass of filaments around 6 arc minutes in length and 4 arc minutes in width.
When seen in a three-dimensional view, it is thought to be having an oblate spheroid or a prolate spheroid.
The filaments are remnants of the atmosphere of the progenitor star. These filaments contain ionized hydrogen, helium, oxygen, carbon, nitrogen, neon, sulfur, and iron.
The temperature of the filaments is around 11,000 K to 18,000 K and their densities are around 1,300 particles per cubic centimeter.
The distance from Earth is 6,290 ± 360 lightyears. The crab nebula is expanding at around 930 miles per second.
The diameter of the crab nebula is 10 lightyears.
The mass of crab nebula is thought to be 4.6±1.8 solar masses.
Constituents of the Nebula
There are two faint stars at the center of the crab nebula. One of the two stars is responsible for the very existence of the nebula.
Crab pulsar (one of the stars in the center of the Crab nebula) has a diameter of 28 to 30 kilometers.
This pulsar is pumping a lot of energy into the nebula. It is producing energy at the rate of a hundred thousand suns! Go figure!
The star that has exploded as a supernova is generally referred to as the progenitor star of the supernova.
What, How and Why of the Crab Nebula
What is a supernova nebula?
When a star dies a violent death, its matter is spewed out in the open which eventually creates an ever-expanding wave of dust and gas. This is called supernova nebula.
How supernova remnants are formed?
The remnants of supernova are formed when the pressure inside the star is stronger than the gravity which holds the star together.
When the pressure inside the star is greater than the gravity, the star explodes.
Why is crab nebula so important?
Crab nebula, as mentioned above, is one of the first nebulas to be discovered. This made the scientists understand about supernovae, progenitor stars, etc. It is also used as a calibration source in X-ray astronomy.
Note: calibration source is a test used for comparing a device to know some unknown value with a device of known and standardized value (here the crab nebula serves as an object with a known value and is used to calculate the value of another object).
How old is the crab nebula?
Crab nebula is around 1,001 years old.
Which galaxy hosts the crab nebula?
Crab nebula is present in our milky way galaxy.
General Facts About Crab Nebula
Crab nebula ejects gas and dust at a speed of 3 million miles per hour or 4.8 million kilometers per hour.
You can actually see the crab nebula with binoculars but you can just a dim patch. With a 16-inch telescope, you can actually have a good look at the nebula.
In 1967, Charles Schisler, a U.S. Air Force officer, observed a fluctuating radio source. He noticed this source for many days.
He even noticed that the position coincided with the position of the crab nebula.
In 1968, Puerto Rico observed the same fluctuating radio source and after further studies discovered the crab pulsar.
Crab pulsar flashed 30 times per second!
We will end our article on crab nebula facts here. If you want to know anything more on this topic, all you have to do is drop a comment and we will respond!