by Astronomers have presented an explanation for the shapes of planetary nebulae. The discovery is based on a set of observations of stellar winds around aging stars. Contrary to common consensus, the team found that stellar winds are not spherical, but have a shape similar to that of planetary nebulae.
Dying stars swell and cool to eventually become red giants. They produce stellar winds, flows of particles that the star expels, which causes them to lose mass. Because detailed observations were lacking, astronomers have always assumed that these winds were spherical, like the stars they surround.
As the star evolves further, it heats up again and the stellar radiation causes the expanding ejected layers of stellar material to glow, forming a planetary nebula.
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Dying stars swell and cool to eventually become red giants. They produce stellar winds, flows of particles that the star expels, which causes them to lose mass. Because detailed observations were lacking, astronomers have always assumed that these winds were spherical, like the stars they surround.
As the star evolves further, it heats up again and the stellar radiation causes the expanding ejected layers of stellar material to glow, forming a planetary nebula.
Continued...
Source
