NASA's James Webb Space Telescope has captured new infrared images of the Lion Nebula, officially known as NGC 2392, located 5,000 light-years from Earth in the constellation Gemini.
The nebula gets its nickname from its striking resemblance to a lion. Hazy structures around the outer edge form a lion's mane, while the stellar core sitting at the centre resembles a button nose.
A planetary nebula is an expanding shell of glowing gas expelled by a dying star late in its lifecycle. The Lion Nebula formed when its oxygen-rich central star exhausted its nuclear fuel and died, shedding its outer layers into space and leaving behind a dense stellar core known as a white dwarf.
"Webb's imagery 'freezes' this planetary nebula in time, though the star's death, and its tumultuous effects, go on," NASA explained. Space agency scientists noted that NGC 2392 will continue to undergo changes as its gas and dust migrate away from the central core. Astronomers estimate that the lion will eventually disperse in approximately 10,000 years, which is a relatively short period in astronomical terms.
Infrared observations reveal detailed cosmic structures
The Lion Nebula was first photographed in visible light by NASA's Hubble Space Telescope in 2000. Now, the James Webb Space Telescope has provided an even sharper look at the cosmic object in infrared light, which can penetrate thick clouds of interstellar dust more effectively than optical telescopes.
Webb observed the nebula using two of its primary imaging instruments: the Near Infrared Camera, known as NIRCam, and the Mid Infrared Instrument, or MIRI. The newly released photographs reveal several internal features of the nebula in unprecedented detail.
At the centre of NGC 2392 lie the remains of the star itself. "In the Lion Nebula, the oxygen-rich central star has died and left behind a white dwarf that is effectively 'cooking' the nebula from within," NASA explained.
The intense radiation produced by the white dwarf creates an expanding bubble of ionized gas that forms the lion's recognizable face. As this bubble grows, it sweeps outward and destroys dust in its path. Astronomers are still working to understand why this swept-up gas forms such complicated arrangements of rings and shells, which are structures commonly seen in planetary nebulae.
Referring to the central stellar remnant, NASA said: "Though it looks like the button nose of the lion, its energy and radiation are powering the intricate structures seen here."
Meanwhile, the lion's mane corresponds to the inner region of an extensive dust shell surrounding the core. "Within it are structures that resemble tufts of hair or comet-like tails," NASA explained. "These features are actually compact clumps of dust that have managed to withstand radiation from the stellar core. By blocking some of that radiation, the dense clumps also shield material located behind them."
What the discovery means for the future of Earth and the Sun
The life cycle of NGC 2392 provides astronomers with a glimpse of what will eventually happen to our own solar system. Five billion years from now, scientists calculate that the Sun will have grown into a red giant star, expanding to more than 100 times its current size.
Eventually, the Sun will eject its outer layers of gas and dust to create an envelope accounting for as much as half of its total mass. The remaining core will become a tiny white dwarf star, which will shine for thousands of years while illuminating the surrounding envelope to create a ring-shaped planetary nebula.
While this stellar metamorphosis will fundamentally change the solar system, scientists remain unsure about the exact fate of Earth, the third rock from the Sun. Researchers already know that the expanding Sun will become significantly bigger and brighter, which will probably destroy any form of life on the planet. However, whether Earth's rocky core will survive the ordeal remains uncertain.
