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How does a stellar wind contribute to the formation of a planetary nebula?

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Planetary nebula Southern Ring Nebula as captured by the James Webb Space Telescope in the near-infrared (left) and the mid-infrared (right). The dimmer star at the center of this scene has been sending out rings of gas and dust for thousands of years in all directions. The Southern Ring Nebula is approximately 2,500 light-years away.

A stellar wind plays a critical role in the formation of a planetary nebula by facilitating the mass loss that eventually exposes the star's hot core.1

Before the nebula is ejected, the star exists as a red giant. During this phase, it experiences a rapid loss of mass through a comparatively slow-moving stellar wind, which can lose up to 0.01 Earth masses per day. This wind may be heavily obscured by dust formed from heavy elements.1

As the star continues to lose its overlying atmosphere, its hot core is eventually exposed. This core emits radiation that ionizes the surrounding gas—the material that was previously ejected as the stellar wind. This ionization zone expands outward through the slowly moving material, creating the visible nebula. The expansion speed of this gas is typically about 30 km (19 miles) per second. Ultimately, the mechanism of this mass loss is highly efficient at ejecting the star's hydrogen-rich outer layers, leaving behind a dense white dwarf core.12