Crab Nebula or M1

The Crab Nebula (M1, NGC 1952) the result of a supernova explosion, which occurred in the 11th century and described by many Chinese astronomers of the Song Dynasty, from 1054 to 1056. In the West, the nebula was noticed for the first time in 1731 by John Bevis, and Charles Messier in 1758, while searching for Halley's comet which he expected to return this year. The Crab Nebula provides an opportunity for Charles Messier to create a catalog of nebulae, the Crab Nebula M1, is the first object of this catalog. It is located 6,300 light-years away in the constellation Taurus. A pulsar illuminates the central region of the nebula, the Crab pulsar rotates very quickly on itself, about thirty times per second. Astronomers estimate that the pulsar emits 200,000 times more energy than the Sun. The expansion velocity of the nebula, to calculate what time it exploded, the supernova exploded, there are about 900 years. Thus we made the connection with the explosion described in the 11th century, in April or May 1054, by the Chinese and Arabs. This star was then described as the brightest of all the other celestial bodies, after the moon. It remained visible during the day, 23 days. In the center of the Crab Nebula can be seen two stars which one of them, is the cause of the nebula.

The progenitor star, very small, 30 km in diameter, emits radio waves, X-rays, gamma rays and brief pulse every 33 milliseconds, making it a pulsar. Pulsars are the remains of the explosion of massive stars, a dozen solar masses, and they emit strong electromagnetic radiation, many times per second. The central region of the Crab nebula is swept by a shock wave, moving in very short periods, a few days.

Image:  The most famous supernova in the history of astronomy. SN 1054 was a supernova whose explosion was seen from the Earth from 1054, now called the Crab Nebula. It is located in the Taurus constellation in our galaxy. This new Hubble image, is one of the most important image ever produced with an observatory in Earth orbit. It shows a whole view, the most detailed to date, the Crab Nebula. The Crab is arguably the most interesting subject, and also one of the most studied in the world of astronomy. The image of this nebula is the largest image ever taken with Hubble camera. It was assembled from 24 individual exposures taken by the Hubble telescope.

Multiple observations were made over several months, with the telescope Chandra X-ray Observatory (NASA) and the Hubble Space Telescope (NASA / ESA). The show was wonderful, matter and antimatter were propelled at the speed of light through the heart of the Crab. Astronomers have seen a pulsar, that is a rapidly rotating neutron star, the size of Manhattan. In the year 1054 AD, Chinese astronomers were surprised by the appearance of this new star, so bright, it was visible in broad daylight and this, for several weeks. Today, the Crab Nebula is visible at the place of the bright star. Crab nebula is still expanding at a speed of 1500 km/s, which is consistent with the date of its discovery in 1054. In the center of the Crab Nebula can be seen two stars which one of them, is the cause of the nebula. These two stars are nestled in a small internal planetary nebula (picture opposite), the bluish glow in the heart of the great Crab nebula.

This nebula is very useful to astronomers because it is located very close to the ecliptic plane and emits strong radiation source which allows to observe other celestial objects when they pass nearby. The thickness of the atmosphere of Titan, Saturn's moon, was measured by the X-ray emission of the Crab. 

Image: The filamentary structure of the Crab Nebula is detailed here, by the Hubble Space Telescope.
Credit: NASA/ESA and The Hubble Heritage Team STScI/AURA

The wispy cloud and filamentary gas and dust that is the Crab Nebula is the remnant of a supernova explosion that was observed by Chinese astronomers in the year 1054. This supernova behind the Crab nebula is probably appeared in April or May 1054. It reached two months later, in July 1054, a maximum apparent magnitude between -5 and -3 (see table below against magnitudes). Its brightness was then equivalent to that of Venus brighter than all the stars in the night sky. The image against combines two views, Hubble's view in visible wavelengths, shown in blue and the image taken Herschel far-infrared which reveals the dust of the nebula, shown here red. While studying the dust content of the Crab Nebula with Herschel, a team of astronomers has detected emission hydride argon lines, a molecular ion of the noble gas argon. This is the first time that scientific detect in space, a compound based on a noble gas.
The central star of the nebula, the origin of this remnant, is now a little bright star in the visible domain against it is extremely bright in the field of gamma rays and X-rays. The Crab pulsar emits pulses of light every 33 milliseconds but the pulse frequency decreases steadily, which means that the rotation of the pulsar slows regularly despite tremors passengers that neutron stars.

Image: composite image of the Crab Nebula, a supernova remnant iconic in our galaxy, the Milky Way. View from the Herschel Space Observatory and the Hubble Space Telescope. The blue color represents the image of the hubble space telescope and the red color represents the image of the Herschel space telescope. Herschel (ESA) is an ESA mission with significant contributions from NASA and Hubble (NASA) is a NASA mission with significant contributions from ESA. Credit image: ESA / Herschel / PACS / MESS Key Program supernova team ; NASA, ESA Allison Loll / Jeff Hester (Arizona State University).