The tendrils form as the material expands into the gas and dust that surrounded the progenitor star.

这些卷须是在物质膨胀成环绕在恒星周围的气体和尘埃时形成的。

I suspect this is why we see so many weird and fantastic shapes in planetaries: their progenitor stars swallowed their planets.

它们的祖先恒星吞噬了它们的行星。