The
Owl Nebula (also known as
Messier 97,
M97 or
NGC 3587) is a starburst
("planetary") nebula approximately 2,030
light years away in the
northernconstellationUrsa Major. The estimated age of the Owl Nebula is about 8,000 years. It is approximately circular in cross-section with faint internal structure. It was formed from the outflow of material from the
stellar wind of the central
star as it evolved along the
asymptotic giant branch. The nebula is arranged in three concentric shells/envelopes, with the outermost shell being about 20–30% larger than the inner shell. A mildly owl-like appearance of the nebula is the result of an inner shell that is not circularly symmetric, but instead forms a barrel-like structure aligned at an angle of 45° to the line of sight.The nebula holds about 0.13
solar masses (M☉) of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur; all with a density of less than 100 particles per cubic centimeter. Its outer radius is around 0.91 ly (0.28 pc) and it is expanding with velocities in the range of 27–39
km/s into the surrounding
interstellar medium.The 14th
magnitude central star has passed an apex of its
evolution so is condensing to form a
white dwarf.=10.5px It has 55% to 60% of solar mass, is 41 to 148 times solar luminosity (L☉), and has an
effective temperature of 123,000 K. The star has been successfully resolved by the
Spitzer Space Telescope as a point source that does not show the
infrared excess characteristic of a
circumstellar disk.
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