The bar’s length is roughly 500times the diameter of Pluto’s orbit around the Sun and, according to the team, the mass of iron atoms is comparable to the mass of Mars. The Ring Nebula, first spotted in 1779 in the northern constellation of Lyra by the French astronomer Charles Messier, is a colourful shell of gas thrown off by a star as it ends the nuclear fuel-burning phase of its life. Our own Sun will expel its outer layers in a similar way in a few billion years’ time.
The hot Iron cloud was discovered in observations obtained using a new instrument installed on the Isaac Newton Group’s 4.2-metre William Herschel Telescope (WHT) on the island of La Palma. The instrument is called the WHT Enhanced Area Velocity Explorer (WEAVE) and it allows images of the Nebula to be viewed at all wavelengths within the range of the instrument. Lead author Dr Roger Wesson, based jointly at UCL’s Department of Physics & Astronomy and Cardiff University, said: “Even though the Ring Nebula has been studied using many different telescopes and instruments, WEAVE has allowed us to observe it in anew way, providing so much more detail than before."
By scrolling through the images, the image at 4227 Angstroms, which is associated with four times ionized Iron atoms [Fe V], stood out as being completely different to the distribution of other elements, see Figure 2. The origin of the Iron bar is a mystery, and the team is requesting further observations at higher resolution to try and shed some light on the origin of this feature for a future paper. The discovery paper is published in the Monthly Notices of the Royal Astronomical Society on Friday 16th Jan as 'WEAVE imaging spectroscopy of NGC 6720: an iron bar in the Ring' by Wesson et al.