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 northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Ursa Major Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...

. 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 A stellar wind is a flow of gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric. D ...

of the central

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

as it evolved along the

asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) lat ...

. 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 mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

es () 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 and it is expanding with velocities in the range of 27–39

km/s The metre per second is the unit of both speed (a scalar quantity) and velocity (a vector quantity, which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a ...

into the surrounding

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

. The 14th

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

central star has passed an apex of its

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

so is condensing to form a

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

. It has 55% to 60% of solar mass, is 41 to 148 times solar luminosity (), and has an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 123,000 K. The star has been successfully resolved by the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...

as a point source that does not show the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

excess characteristic of a

circumstellar disk A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the ...

History

The Owl Nebula was discovered by French

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

Pierre Méchain Pierre François André Méchain (; 16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep-sky objects and comets. Life Pierre Méchain was born i ...

on February 16, 1781.

was Charles Messier's observing colleague, and the nebula was observed by Messier himself a few weeks following the initial sighting. Thus, the object was named Messier 97, and included in his

catalog Catalog or catalogue may refer to: *Cataloging **'emmy on the 'og **in science and technology ***Library catalog, a catalog of books and other media ****Union catalog, a combined library catalog describing the collections of a number of libraries ...

on March 24, 1781. Of the object, he noted "Nebula in the great Bear, near Beta: It is difficult to see, reports M. Méchain, especially when one illuminates the micrometer wires: its light is faint, without a star. M. Méchain saw it the first time on Feb 16, 1781, & the position is that given by him. Near this nebula he has seen another one, he position ofwhich has not yet been determined essier 108 and also a third which is near Gamma of the Great Bear essier 109 (diam. 2′)." In 1844, Admiral William H. Smyth classified the object as a

planetary nebula A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelate ...

. When

William Parsons, 3rd Earl of Rosse William Parsons, 3rd Earl of Rosse (17 June 1800 – 31 October 1867), was an Irish astronomer, naturalist, and engineer. He was president of the Royal Society (UK), the most important association of naturalists in the world in the nineteenth ...

, observed the nebula in

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

in 1848, his hand-drawn illustration resembled an

owl Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

's head. In his notes, the object was described as “Two

s considerably apart in the central region, dark

penumbra The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. Assuming no diffraction, for a collimated beam (such as a point source) of light, only the umbra is cast. Th ...

round each spiral arrangement, with stars as apparent centres of attraction. Stars sparkling in it; resolvable.” It has been known as the Owl Nebula ever since. More recent developments in the late 1900s include the discovery of a giant red halo of wind extended around its inner shells, and the mapping of the nebula's structure.

Observing

Although the Owl Nebula can not be seen with the naked eye, a faint image of it can be observed under remarkably good conditions with a small telescope or 20×80 binoculars. To make out the nebula's more distinctive owl like eye features, a telescope with an aperture 10" or better is required. To locate the nebula in the night sky, look to the southwest corner of the

Big Dipper The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ...

's bowl, marked by the star

Beta Ursae Majoris Beta Ursae Majoris (β Ursae Majoris, abbreviated Beta UMa, β UMa), formally named Merak , is a star in the northern constellation of Ursa Major. The apparent visual magnitude of this star is +2.37, which means it is read ...

. From there, M97 lies just over 2.5 degrees in the southeast direction towards the star positioned opposite

in the other bottom corner of the

s Bowl,

Gamma Ursae Majoris Gamma Ursae Majoris (γ Ursae Majoris, abbreviated Gamma UMa, γ UMa), formally named Phecda , is a star in the constellation of Ursa Major. Since 1943, the spectrum of this star has served as one of the stable anchor p ...

; which marks the constellations southwest corner. M97, together with Alpha Ursae Majoris, point the way to

Polaris Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris ( Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude that ...

Gallery

File:The Owl Nebula M97 Goran Nilsson & The Liverpool Telescope.jpg, HaRGB image of the Owl Nebula M97 from the Liverpool Telescope File:M97rosse.jpg, Drawing of the Owl Nebula (M97) by Lord Rosse, who gave the name to the planetary nebula. Source: seds.org File:The_location_of_Messier_97_in_Ursa_Major.png, Location of M97 in Ursa Major

References

External links

The Owl Nebula @ SEDS Messier pages

NightSkyInfo.com – M97, the Owl Nebula
* *
The Owl Nebula (M97) at Constellation GuideMessier 97: Owl Nebula at Messier Objects
{{Sky, 11, 14.8, 00, +, 55, 01, 00, 2600 Messier objects NGC objects Planetary nebulae Ursa Major (constellation) Astronomical objects discovered in 1781 Discoveries by Pierre Méchain

History

Observing

Gallery

See also

References

External links