獅子星雲獨特外觀的動力來源於其中心一顆垂死的低質量恆星。這顆恆星在耗盡核心燃料後，脫落外層形成了行星狀星雲，並留下一顆高溫的白矮星。這顆白矮星的輻射正在從內部加熱周圍物質，產生了不斷膨脹的游離氣體泡（獅子面部），並照亮了周圍的塵埃殼層（獅子鬃毛）。
韋伯望遠鏡的影像如同將這個行星狀星雲的時間凍結，但恆星死亡所帶來的劇烈影響仍在持續。隨著氣體和塵埃繼續遠離恆星核心，NGC 2392 將不斷發生變化，天文學家估計這隻「獅子」最終會在約一萬年後消散，這在天文學尺度上是一段相對短暫的時間。
The James Webb Space Telescope recently captured a clearer, more detailed image of NGC 2392 (the Lion Nebula) using its high-resolution infrared instruments, compared to previous Hubble images. While the overall structure appears similar, Webb's infrared perspective highlights details like compact dust clumps and ionized gas, showcasing the results of the nebula's evolution over thousands of years.
The driving force behind the Lion Nebula's distinct appearance is a dying, low-mass star at its center. After exhausting its core fuel, the star shed its outer layers to form a planetary nebula, leaving behind a very hot white dwarf. The radiation from this white dwarf is heating the surrounding material from the inside, creating an expanding bubble of ionized gas (the lion's face) and illuminating the surrounding dust shell (the lion's mane).
Webb's imagery freezes this planetary nebula in time, yet the tumultuous effects of the star's death are ongoing. As the gas and dust continue to migrate away from the stellar core, NGC 2392 will keep undergoing changes, and astronomers estimate that the "lion" will eventually disperse in approximately 10,000 years, a relatively short period on astronomical scales.