James Webb Captures Lion Nebula in Infrared, Revealing 10,000-Year Fate

Q: If the Lion Nebula fades in 10,000 years, what invisible cosmic forces will finally consume its glowing stellar heart?

The Lion Nebula will not be “consumed” by a hidden predator so much as dispersed by expansion, radiation, and gravity, while its stellar heart survives as a white dwarf. What fades in about 10,000 years is the nebula itself: the glowing gas and dust shell expelled by the dying star. Webb’s observations show that the hot white dwarf at the center is still blasting intense ultraviolet radiation into that material, ionizing it and driving an expanding bubble outward. As the gas spreads farther into space, it thins out, cools, and becomes too diffuse to shine brightly. Dust is also eroded by the harsh radiation and shocks moving through the nebula. The main “invisible forces” shaping that end are electromagnetic radiation from the white dwarf, fast stellar winds, and gravity acting on the expanding debris and the surrounding interstellar medium. Over time, the nebula’s material will simply mix back into interstellar space. The white dwarf itself is not expected to vanish on that timescale. After the nebula disperses, the exposed stellar core will remain as an extremely dense remnant supported by quantum electron-degeneracy pressure, then cool very slowly for billions to trillions of years. In far deeper cosmic time, it would fade toward a hypothetical black dwarf, not be suddenly swallowed. So the glowing lion disappears because its gas shell is blown apart and diluted; its “heart” endures, slowly cooling long after the visible nebula is gone.

3 articles · Updated · European Space Agency · Aug 11

NGC 2392 appears in sharper infrared detail in new James Webb images, exposing compact dust clumps and a haze of ionized gas that were less clear in earlier views.
Webb used both NIRCam and MIRI to look through the planetary nebula, whose lion-like shape is being driven by a central white dwarf powering and reshaping the surrounding material.
The expanding bubble of ionized gas is destroying dust in its path, while surviving comet-like clumps shield material behind them and help create the nebula’s rings, shells and "mane."
Hubble imaged the Lion Nebula in visible light in 2000, but Webb’s infrared view gives astronomers a better snapshot of an object that formed over several thousand years and is expected to disperse in about 10,000 more.