Lion Nebula roars to life for Webb

Observing across the starry “plains” of space, the NASA/ESA/CSA James Webb Space Telescope has taken images of NGC 2392, nicknamed the Lion Nebula.

The NASA/ESA 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, both with the NIRCam (Near Infrared Camera) and MIRI (Mid-Infrared Instrument), may look quite similar to Hubble's earlier visible-light view. However, Webb's infrared vision highlights features like compact clumps of dust and haze of ionised 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 centre: the remains of a dying star. Though it looks like the button nose of the lion, the central white dwarf's energy is powering the intricate structures seen here.

The bubble of ionised gas, which forms the lion’s face, is expanding over time and destroying dust that is in its path. Understanding the reason for 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 centre. 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 are protecting 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 that the lion will eventually disperse in approximately 10,000 years — a relatively short period in astronomical terms.

[Image description: Planetary nebula NGC 2392, also called the Lion Nebula, against the black background of space. The nebula is in the centre, circular in shape, and looks like a male lion’s head. In the very centre is a small, pinkish-white circle with eight-point diffraction spikes, a white dwarf star. Surrounding the star are light purple-pink cavernous bubbles and shell-like rings. The bubbles and shells collectively form an oval with two small, wide arcs near the top, reminiscent of a lion’s face and its ears. What appears to be extended outward from the lion’s face is a thick ring of purple-blue material. The width of the ring is consistent throughout and resembles a mane.]