Lion Nebula Roars to Life With NASA’s Webb

Observing across the starry “plains” of space, NASA’s James Webb Space Telescope has taken new images of NGC 2392, nicknamed the Lion Nebula. NASA’s Hubble Space Telescope previously viewed this planetary nebula in 2000, imaging the lion face-shaped target in visible light and revealing features such as the “mane” of hazy, comet-shaped objects. Now Webb has captured a clearer, more detailed view of the Lion Nebula due to its high-resolution imaging.

At first glance the nebula’s overall structure in Webb’s infrared images, with both the NIRCam (Near Infrared Camera) and MIRI (Mid Infrared Instrument) instruments, may look quite similar to Hubble’s earlier visible-light view. However, Webb’s infrared vision highlights features like compact clumps of dust and a haze of ionized gas. It’s taken several thousand years for this collection of gas and dust to reach its current shape, and the nebula’s components continue to be altered.

The source of these constant changes and the reason for the Lion Nebula’s distinct appearance is located at the center: the remains of a dying star. Though it looks like the button nose of the lion, its energy and radiation are powering the intricate structures seen here.

Massive stars undergo supernova explosions at the end of their lives, but these kinds of events are few and far in between. Most of the universe’s stars have lower masses, like the one belonging to NGC 2392. When a lower-mass star can no longer sustain itself with nuclear reactions in its core, the star becomes unstable and pulsates, losing its mass by shedding its outer layers, which then turn into shells of gas and dust called a planetary nebula. (Stars at this life stage are responsible for producing much of the universe’s observable dust.) The star’s radiation drives the ejected material away, leaving behind the very hot stellar core, also known as a white dwarf.

In the Lion Nebula’s case, the death of the oxygen-rich central star has left behind a white dwarf that is “cooking” everything from the inside and producing a bubble of ionized gas as it does. The gas bubble, which forms the lion’s face, is expanding over time and destroying dust that is in its path. Understanding why the swept-up gas has a complex structure of rings and shells, a common feature in planetary nebulae, is an ongoing endeavor.

The mane of the lion is the interior of a dust shell that is being illuminated by the white dwarf at the center. The tufts of hair, which look like cometary tails of material, are compact clumps of dust that have survived the stellar core’s radiation and protect the material that lies behind them.

Webb’s imagery “freezes” this planetary nebula in time, though the star’s death, and its tumultuous effects, go on. NGC 2392 will continue to undergo changes as its gas and dust migrate away from the stellar core. Astronomers estimate the lion will eventually disperse in approximately 10,000 years — a relatively short period in astronomical terms.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

To learn more about Webb, visit:

https://science.nasa.gov/webb

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