Free Astronomy Magazine November-December 2026

objects. Now Webb has captured a clearer, more detailed view of the Lion Nebula due to its high-res- olution imaging. At first glance the nebula’s overall structure in Webb’s infrared images, both with the NIRCam (Near Infrared Camera) and MIRI (Mid In- frared Instrument), may look quite similar to Hub- ble’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 neb- ula’s components continue to be altered. The source of these con- stant changes and the rea- son for the Lion Nebula’s distinct appearance is lo- cated at the centre: 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 su- pernova explosions at the end of their lives, but these kinds of events are far and few between. Most of the Universe’s stars have lower masses, like the one be- longing to NGC 2392. When a lower-mass star can no longer sustain itself with nuclear reactions in its core, the star becomes un- stable and pulsates, losing its mass by shedding its outer layers, which then turn into shells of gas and dust called a planetary 15 NOVEMBER-DECEMBER 2026 ASTRO PUBLISHING 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 be- hind a white dwarf that is “cooking” everything from the inside and producing a bubble of ionised 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 fea- ture in planetary nebulae, is an ongoing endeavour. 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 protect- ing 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 ap- proximately 10,000 years — a relatively short period in astronomical terms. ! W ebb recently imaged plane- tary nebula NGC 2392, which is nick- named the Lion Neb- ula due to its distinct shape. This near- and mid-infrared compos- ite image reveals the complex structure of the nebula, which has formed and continues to be sculpted by the remains of a dying star. The stellar core, also known as a white dwarf, is lo- cated at the centre and looks like the button nose of the lion. The central dying star is so hot that its radiation is “cooking” everything from the inside and producing a bubble of ionized hydrogen gas as it does. The gas bubble, which is the lion’s “face,” fea- tures cavernous shells and rings with ten- drils that are expand- ing and destroying dust upon encounter. However, not all dust is obliterated from the scene. The lion’s mane is the interior of a dust shell that is being illuminated by the central star’s core. Within the mane some compact clumps of dust (red and or- ange) have managed to survive so far and are protecting the material that lies be- hind them. Additional clumps of molecular hydrogen appear yel- low. [NASA, ESA, CSA, STScI. Image Processing: A. Pagan (STScI)]