Owl Nebula

The Owl Nebula (also known as Messier 97,M97 or NGC 3587) is a planetary nebula located approximately 2,030 light years away in the constellation Ursa Major.[2] It was discovered by French astronomer Pierre Méchain on February 16, 1781.[4] When William Parsons, 3rd Earl of Rosse, observed the nebula in 1848, his hand-drawn illustration resembled an owl’s head. It has been known as the Owl Nebula ever since.[5]

The nebula is approximately 8,000 years old.[6] It is approximately circular in cross-section with a little visible 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.[3] The nebula is arranged in three concentric shells, with the outermost shell being about 20–30% larger than the inner shell.[7] The 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.[3]

The nebula holds about 0.13 solar masses of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur;[3] all with a density of less than 100 particles per cubic centimeter.[7] 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.[3]

The 14th magnitude central star has since reached the turning point of its evolution where it condenses to form a white dwarf.[4][7] It has 55–60% of the Sun’s mass, 41–148 times the brightness of the Sun,[3] and 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]

Content retrieved from: https://en.wikipedia.org/wiki/Owl_Nebula.