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.
[2] The estimated age of the Owl Nebula is about 8,000 years.
[5] 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.
[4] The nebula is arranged in three concentric shells/envelopes, with the outermost shell being about 20–30% larger than the inner shell.
[6] 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.
[4]The nebula holds about 0.13
solar masses (M☉) of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur;
[4] all with a density of less than 100 particles per cubic centimeter.
[6] 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.
[4]The 14th
magnitude central star has passed an apex of its
evolution so is condensing to form a
white dwarf.
[7][6] It has 55% to 60% of solar mass, is 41 to 148 times solar luminosity (L☉),
[4] and has an
effective temperature of 123,000 K.
[8] 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.
[9]
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