Abell 39 is an almost perfectly spherical planetary
nebula in the constellation Hercules. Discovered
in 1966 by George Abell, it is one of the largest known spheres in our Galaxy.
Its shape has allowed astronomers to accurately estimate how much relative
material in the nebula is absorbing and emitting light. Observations indicate
that Abell 39 contains has only about half the abundance of oxygen found
in the sun. The reason why the central star is slightly off center, by 0.1
light-year, is currently unknown.
| Abell 39. Credit: George Jacoby
(WIYN Obs.) et al., WIYN, AURA, NOAO, NSF
15.7 (central star)
||~ 7,000 light-years
||R.A. 16h 27m 32.6s;
Dec. +27° 54' 29"
PK 047+42.1, ARO 180
AND STAR CLUSTERS