NASA's James Webb Space Telescope has produced a new infrared view of NGC 2392, the Lion Nebula, revealing compact dust clumps, ionized gas and nested shells shaped by the remains of a dying star. NASA released the observation on August 10 with contributions from the European and Canadian space agencies and the Space Telescope Science Institute.
The planetary nebula formed after a lower-mass, oxygen-rich star exhausted the nuclear reactions that supported it. The unstable star pulsated and shed its outer layers over several thousand years, leaving a very hot white dwarf whose radiation now drives the expelled gas outward. Despite its name, a planetary nebula is not related to planets.
Webb combined data from its Near-Infrared Camera and Mid-Infrared Instrument. The infrared measurements sharpen features that appeared hazier in a visible-light Hubble image from 2000: a face-like bubble of ionized gas surrounds the central white dwarf, while a broad illuminated dust shell forms the apparent mane. The instruments also distinguish rings, shells and material with comet-like tails.
NASA said the expanding inner bubble is destroying dust in its path, while dense clumps withstand the central star's radiation and shield material behind them. Mid-infrared data show that some dust filaments continue to survive. Astronomers are still investigating why planetary nebulae commonly develop such complicated rings and shells instead of simpler, evenly expanding structures.
The observation gives researchers a detailed snapshot of a brief stage in the life cycle of ordinary stars, which produce much of the observable dust in the universe. The gas and dust in NGC 2392 will keep moving away from the white dwarf, and astronomers estimate that the recognizable nebula will disperse in roughly 10,000 years. Future analysis can use Webb's complementary infrared bands to trace how radiation reshapes stellar debris.
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