
News + Trends
Webb telescope shows the "Eye of Sauron" in new depth of detail
by Samuel Buchmann

New images from the James Webb Space Telescope show the Helix Nebula in unprecedented detail. They reveal complex structures around the hot central object and provide insights into the material forge of future star and planetary systems.
The Helix Nebula (NGC 7293) has been one of the best-known planetary nebulae in the sky since its discovery by the German astronomer Karl Ludwig Harding more than two centuries ago. It is located around 650 light years from Earth in the constellation of Aquarius (Aquarius in Latin) and is therefore one of the closest objects of its kind to us. The large ring-shaped structure of expanding gas and dust is the remnant of a once sun-like star that shed its outer shell at the end of its life. Its striking appearance has also earned the nebula a few imaginative nicknames: the structure is also known as the «eye of God» - or as that of Sauron, a fictional character from the fantasy epic «The Lord of the Rings».
In the centre of NGC 7293 sits a dazzlingly bright white dwarf, the exposed core of the dying progenitor star, barely recognisable as a small blue dot. Its intense, high-energy radiation lights up the surrounding gas and creates a variety of structures there. The new detailed image taken with the NIRCam, the Near Infrared Camera on board the James Webb Space Telescope (JWST), shows hundreds of comet-like pillars with bright heads and extended, outward-facing tails. Densely packed, they form the inner edge of the «eye». They form where the hot, fast stellar winds of the central white dwarf meet slower and cooler layers of gas that it has ejected at an earlier time.

The colour in the JWST infrared image reveals a lot about the temperature and chemical composition of the gas. Bluish tones mark strongly heated gas ionised by the intense ultraviolet radiation of the white dwarf in its immediate vicinity. Further outwards, the gas cools down, hydrogen atoms combine to form molecules, while dust can form in the outer, reddish peripheral areas. There, shielded from the high-energy radiation, in the dark areas, amidst the glowing orange and red tones, complex molecules are formed - the raw material that could one day become new stars and planets.
Studies with Spitzer, NASA's infrared space telescope that was shut down in 2020, already pointed to the formation of complex molecules; but it is Webb's unrivalled resolution that makes it possible to watch them form.
Due to its relative proximity, the Helix Nebula is a favourite target for amateur astronomers and scientists alike. However, its comparatively large apparent diameter in the sky of about half the width of a full moon should not obscure the fact that planetary nebulae are rather compact and, with lifetimes of a few tens of thousands of years, quite short-lived phenomena on a cosmological scale.
We are partners of Spektrum der Wissenschaft and want to make well-founded information more accessible to you. Follow Spektrum der Wissenschaft if you like the articles.
Experts from science and research report on the latest findings in their fields – competent, authentic and comprehensible.
From the latest iPhone to the return of 80s fashion. The editorial team will help you make sense of it all.
Show all