Owl Nebula
Lua error in Module:Infobox at line 235: malformed pattern (missing ']'). The Owl Nebula (Messier 97,M97, 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]
See also
References
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<references />, or <references group="..." />External links
- The Owl Nebula @ SEDS Messier pages
- The Owl Nebula at Calar Alto Observatory
- NightSkyInfo.com – M97, the Owl Nebula
- The Owl Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
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- The Owl Nebula (M97) at Constellation Guide
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Coordinates: 
11h 14.8m 00s, +55° 01′ 00″[[Category:Orion–]
- ↑ 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Per Guerrero et al. (2003), the age is 12,900 × d years, where d is the distance in kpc. According to Stanghellini et al. (2008), d is 0.621 kpc. Hence, the age is 12,900 × 0.621 ≈ 8,000 years.
- ↑ 7.0 7.1 7.2 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Lua error in package.lua at line 80: module 'strict' not found.
