The 'Eye of Sauron'

 Extreme Closeup of  The 'Eye of Sauron' with JWST 

The Webb space telescope has stared deep into the darkness of the Helix Nebula, revealing layers of gas shed by a dying star to seed the cosmos with future generations of stars and planets. We know what will happen to the Sun and our Solar System because we can look outward into the galaxy and examine older Sun-like stars in their evolutionary end states. The new image offers a rare look at the fate of our own star and planetary system. Nothing lasts forever, including a star's fuel. Eventually, stars deplete their hydrogen and leave the main sequence behind. Stars with masses similar to the Sun will first swell and turn red, then shed their outer layers. That's what we see when we gaze at older Sun-like stars. But the fun doesn't end there. The once-great star then illuminates these gases and ionizes them, creating one of nature's most beautiful displays: a planetary nebula (PN). The Helix Nebula is beloved among amateur astronomers and astrophotographers because it looks like a giant eye, so much so that it's sometimes playfully called the 'Eye of Sauron.' The Helix Nebula is one of the closest bright PN to Earth. It's around 650 light-years away in the constellation Aquarius.

A new Webb image captures a zoomed-in view of the iconic nebula, also known as the Eye of Sauron or Eye of God for its piercing, eye-shaped appearance. At its center is a blazing white dwarf, the leftover core of a dying star, releasing an avalanche of material which crashes into a colder surrounding shell of gas and dust. The image provides a glimpse into the future of stars like the Sun once they’ve reached the end of their life cycle, recycling material of their own to birth new planetary systems. Readers will know it from the Hubble's well-known portrait of the stunning nebula. A volunteer team of astronomers called the Hubble Helix Team organized a nine-orbit campaign to capture the iconic image. But as we know, there's a new sheriff in town: the James Webb Space Telescope. We waited with great anticipation for the JWST to finally come to fruition. Not only because of the cosmic knowledge it's delivering, but because we love pictures of beautiful stellar objects. While the Hubble's image of the Helix Nebula will always have a place in our star-gazing hearts, the JWST has drawn us even deeper into one of our favourite planetary nebulae.

Using Webb’s NIRCam (Near-Infrared Camera), the small portion of the Helix Nebula comes into full view to reveal comet-like knots, blazing stellar winds, and layers of gas. The high-resolution image shows cloudy pillars which resemble flames surrounding the inner region of an expanding shell of gas. Winds of fast-moving, hot gas from the dying star crash into slower, colder shells of gas and dust shed by the star at an earlier point in its life, creating the nebula’s unique shape. The white dwarf, out of the frame of Webb’s zoomed-in image, lies at the heart of the nebula. Radiation from the dying star lights up the surrounding gas, creating layers of material like a cosmic lasagna. Closest to the white dwarf is hot ionized gas, with cooler molecular hydrogen farther out and protective pockets within dust clouds where more complex molecules can start to form. This is the raw material which could eventually mold itself into planets and star systems. In the Webb image, the temperature and chemistry of the material are represented by different colors. The blue hue marks the hottest gas in this field, energized by intense ultraviolet light from the white dwarf. Farther out, the gas cools into the yellow regions where hydrogen atoms join into molecules. 

At the nebula’s outer edges, reddish tones mark the coolest material, where thinning gas gives way to dust formation, according to NASA. Powerful stellar wind and radiation from the dying star are blowing away the surrounding gas from the star's expelled outer layers. But there are denser knots of material among the gas, and they're resisting the onslaught. They're sometimes called globules, and even cometary knots, because they look like comets leaving dust and vapour trails as they travel through space. We can only see them in the closest PNe, but astronomers think they're a common feature. The Helix Nebula features around 40,000 cometary knots. The amazing thing is, each one probably covers more space than our Solar System, when measured out to Pluto's orbit. And these systems are nowhere near as massive. The head of each knot is well-illuminated and ionized by the nebula's star, while a tail of less well-energized gas trails behind. Zoomed-in image highlights cometary knots in the Helix Nebula. 

The nebula was first spotted in the 1800s and has since become one of the most iconic features of our night skies for its striking shape and proximity. Located just 650 light-years away from Earth in the constellation Aquarius, the eye-shaped nebula is one of the closest of all bright planetary nebulae to our planet’s view. In astronomical terms, planetary nebulae like the Helix Nebula don't last long. It's about 10,000 to 12,000 years old, which is kind of old for a planetary nebula. Its progenitor star started shedding its outer layers between about 15,000 and 20,000 years ago. For the next 10,000, maybe 20,000 years, Helix will continue to expand. Its gas will thin out, and as the white dwarf cools, less radiation will light the gases up. It will grow dimmer and fainter, and will cease to be. Somewhere around 50,000 years after its formation, it will be dispersed into and become part of the interstellar medium. 

This is our Sun's final fate. As it nears the end of its life on the main sequence, it will expand into a red giant. The once-yellow Sun, which will have turned a glowering red, will not be able to maintain its gravitational hold on its gaseous outer layers. They'll be shed into space, then lit up by the long-lived remnant of the Sun, a white dwarf. The white dwarf will be a fading stellar cinder, emanating only remnant heat for billions of years. The nebula and its colours represent a dying star's final gasp, a stellar exhalation which spreads star-stuff out into the cosmos. The material could be taken up in the next round of star formation. Some of this material may even become part of a planet or planets in the future. Maybe one of them will be rocky, with liquid water. Perhaps sometime in the future, some of this water will sit in a warm little pond on the surface of this new world. Astronomers have used ground-based and space observatories to stare into the Eye of Sauron, observing the final moments of a dying star in great detail for everyone.