Photo: ESO, VISTA, NASA, ESA, CSA, STScI, J. Emerson (ESO); Acknowledgment: CASU
The Helix Nebula, located in the constellation Aquarius.
Using the James Webb Space Telescope, scientists have obtained close-up images of the famous “Eye of Sauron.” This is the Helix Nebula, situated about 650 light-years from Earth in the constellation Aquarius, Science Alert reports.
We know how the life of the Sun and the Solar System will end because astronomers can observe other stars in our galaxy at different stages of their evolution. Eventually, stars exhaust their hydrogen and leave the main sequence. Stars with masses similar to the Sun first expand into red giants and then shed their outer layers. But the story does not end there. What remains of the star illuminates these expelled gases, creating what is known as a planetary nebula.
The Helix Nebula is a favorite target of amateur astronomers and astrophotographers because it resembles a giant eye. It is one of the closest planetary nebulae to Earth. One of its most famous images was taken by the Hubble Space Telescope.
Now, however, the “Eye of Sauron” has been imaged by the James Webb Space Telescope, whose snapshot reveals the nebula in unprecedented detail.
Powerful stellar winds and radiation from the dying star blow the surrounding gas outward from the star’s expelled outer layers. But within this gas are denser clumps of matter that resist this pressure.
These are sometimes called globules or cometary knots because they resemble comets, leaving dusty, vapor-like trails as they move through space. So far, they have been detected only in nearby planetary nebulae, but astronomers believe they may be a fairly common phenomenon.
The Helix Nebula contains around 40,000 such cometary knots. Each of them is likely larger than the Solar System out to the orbit of Pluto.
On astronomical timescales, planetary nebulae like the Helix Nebula are short-lived. Its age is estimated at about 10,000–12,000 years, which is already quite old for a planetary nebula. Its progenitor star began shedding its outer layers roughly 15,000–20,000 years ago.
Over the next 10,000 to 20,000 years, the nebula will continue to expand. The gas will become more diffuse, and as the white dwarf cools, its radiation will weaken. The nebula will fade and eventually disappear. About 50,000 years after its formation, it will disperse and become part of the interstellar medium.
