I LOVE seeing posts about new images from the JWST, and Heidi B. Hammel’s post on Halloween was a dozy! The Crab Nebula was imaged in amazingly high resolution by the JWST, and images are available for download HERE.
When I say amazingly high resolution, I meant it! The full-rez TIF image is 10509 x 9151 pixels, and is 147 megabytes in size – this could easily cover and entire wall! A crop showing the central pulsar and synchrotron emissions was still over 3K in size!
Crab Nebula Story
In the year 1054, an intensely bright star appeared in the constellation Taurus, and shone for 23 days before fading. This event would have been visible to everyone living in the northern hemisphere; Chinese, Japanese and Islamic astronomers recorded the event – the Chinese referring to it as a ‘Guest Star.’
The Crab Nebula was first discovered in 1731 by unlucky amateur astronomer John Bevis – the Crab Nebula was to be included in a star atlas he was working on, but his printer went bankrupt; John died from injuries he sustained falling off his telescope in 1771. Note: I can’t find any references to what type of telescope he fell off of, but some of the telescopes at that time were enormous! What I did find was a rabbit-hole of interesting links and information on the man, and a lectures-worth of material!
The Crab Nebula was independently rediscovered in 1758 by Charles Messier – which he thought was Halley’s comet. He noticed that the Crab was not moving against the background of stars like a comet, and thought it would be a fine idea to catalog such objects to avoid miscataloging them as comets – giving birth to the “Messier catalogue.”
In the early twentieth century, analysis of photographs taken of the Crab Nebula several years apart revealed that the nebula was expanding – tracing that expansion backwards, it was determined that the nebula (or something) would have been visible about 900 years earlier. A search of historical records revealed that the “Guest Star” mentioned above was in the right part of the sky; The Crab Nebula became the first astronomical object to be connected to a supernova explosion in 1939.
The Crab Nebula is expanding at 0.5% the speed of light (1,500 km/s), and in the nine centuries since the Crab progenitor star went supernova, the remnant has expanded to 11 light years in size.
Along Came the Pulsars
After the discovery of the first pulsar in 1967 by Jocelyn Bell Burnell, it was predicted by Franco Pacini that the Crab Nebula also contained a pulsar – which was discovered the very next year. The Crab Pulsar is about 20 km in diameter, has a rotational period of about 33 milliseconds; its period was discovered using the now defunct Arecibo radio observatory. The visualization below shows a snapshot in time from way WAY too close to the Crab pulsar – the environment would be chaotic, and the radiation hellscape!
The Vatican Advanced Technology Telescope imaged the Crab Nebula – I’d be remiss if I did not mention that!
The Hubble Space Telescope imaged the Crab Nebula in 2005 – the downloadable image is 3864×3864 pixels in size. That’s pretty big, but it doesn’t hold a candle to the JWST’s 10K image size!
Pulsars slowly (very slowly) lose rotational energy through several means – one of them being gravitational wave radiation; The Crab pulsar has been observed using the LIGO observatory, and in 2008 was the first pulsar to have its spin-down limit of 3.7×10−10 Hz/s determined.
In 2019 the Crab Nebula (and therefore the Crab Pulsar), emitted gamma rays in excess of 100 TeV – making it the first source of ultra-high-energy cosmic rays to be identified, and confirmed it to be a poor vacation destination.
In 2023, Very long baseline interferometry (VLBI) was used to measure the precise distance to the Crab Pulsar of 1.90 (+0.22/-0.18) kpc, or 6196.97 ly. These results are consistent with Gaia 3 measurements.
I can’t remember when I learned of the existence of the Crab Nebula, and neither can my wife. But I know when my granddaughter first learned of it – that would be TODAY! And she said “Oh WOW! That’s pretty!”
Video: Tour of the Crab Nebula
Original NASA Press Release: https://www.nasa.gov/missions/webb/the-crab-nebula-seen-in-new-light-by-nasas-webb/