Structure and Composition
The bright rim of the planetary nebula has an average thickness of about 10″.1 or about 0.34 light-years. There is a faint halo that extends about 18″ beyond the bright rim giving a complete diameter of around 190″ under the assumption that this emission is uniform around the planetary nebula.
This planetary nebula has been expanding for an estimated 22,100+1700
−1500 years, based on an assumed expansion velocity between 32 and 37 km/s and a 0.78 parsec radius.
Background galaxies are visible near the nebula, and some can be seen through the translucent nebula.
Oxygen is only about half as abundant in the nebula as it is in our own sun.
Read more about this topic: Abell 39
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—Paul Tillich (1886–1965)
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