|Observation data: J2000.0 epoch|
|Right ascension||05h 46m 46.7s|
|Declination||+00° 00′ 50″|
|Distance||1,350 ly (415 pc) ly|
|Apparent magnitude (V)||8.3|
|Apparent dimensions (V)||8′ × 6′|
|Notable features||Part of the Orion Complex|
|Designations||Ced 55u, DG 80, IRAS 05442-0000, [KPS2012] MWSC 0664, NGC 2068|
Messier 78 or M78, also known as NGC 2068, is a reflection nebula in the constellation Orion. It was discovered by Pierre Méchain in 1780 and included by Charles Messier in his catalog of comet-like objects that same year.
M78 is the brightest diffuse reflection nebula of a group of nebulae that includes NGC 2064, NGC 2067 and NGC 2071. This group belongs to the Orion B molecular cloud complex and is about 1,350 light-years distant from Earth. M78 is easily found in small telescopes as a hazy patch and involves two stars of 10th and 11th magnitude. These two B-type stars, HD 38563 A and HD 38563 B, are responsible for making the cloud of dust in M78 visible by reflecting their light.
The M78 cloud contains a cluster of stars that is visible in the infrared. 0.3 M☉ to 5 M☉. About 45 variable stars of the T Tauri type, young stars still in the process of formation, are members as well. Similarly, 17 Herbig–Haro objects are known in M78.Due to gravity, the molecular gas in the nebula has fragmented into a hierarchy of clumps, whose cores have masses ranging from
A nebula is a distinct body of interstellar clouds. Originally, the term was used to describe any diffused astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others. Edwin Hubble discovered that most nebulae are associated with stars and illuminated by starlight. He also helped categorize nebulae based on the type of light spectra they produced.
The Orion Nebula is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the night sky. It is 1,344 ± 20 light-years (412.1 ± 6.1 pc) away and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light-years across. It has a mass of about 2,000 times that of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula.
An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically a cloud in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light years, and density from a few to about a million particles per cubic cm. The Orion Nebula, now known to be an H II region, was observed in 1610 by Nicolas-Claude Fabri de Peiresc by telescope, the first such object discovered.
The Trifid Nebula is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum-Centaurus Arm. It was discovered by Charles Messier on June 5, 1764. Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula, a reflection nebula, and a dark nebula. Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers.
The Tarantula Nebula is an H II region in the Large Magellanic Cloud (LMC), from the Solar System's perspective forming its south-east corner.
The Lagoon Nebula is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as an H II region.
The Beehive Cluster, is an open cluster in the constellation Cancer. One of the nearest open clusters to Earth, it contains a larger population of stars than other nearby bright open clusters. Under dark skies, the Beehive Cluster looks like a small nebulous object to the naked eye, and has been known since ancient times. Classical astronomer Ptolemy described it as a "nebulous mass in the breast of Cancer". It was among the first objects that Galileo studied with his telescope.
Messier 46 or M46, also known as NGC 2437, is an open cluster of stars in the slightly southern constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." It is about 5,000 light-years away. There are an estimated 500 stars in the cluster with a combined mass of 453 M☉, and it is thought to be a mid-range estimate of 251.2 million years old.
The Little Dumbbell Nebula, also known as Messier 76, NGC 650/651, the Barbell Nebula, or the Cork Nebula, is a planetary nebula in northern constellation Perseus. It was discovered by Pierre Méchain in 1780 and included in Charles Messier's catalog of comet-like objects as number 76. It was first recognised as a planetary nebula in 1918 by the astronomer Heber Doust Curtis. However, there is some contention to this claim, as Isaac Roberts in 1891 did suggest that M76 might be similar to the Ring Nebula (M57), being instead as seen from the side view. The structure is now classed as a bipolar planetary nebula (BPNe), denoting two stars which have burst, leaving neutron star or white dwarf remnants and luminous envelopes. Distance to M76 is currently estimated as 780 parsecs or 2,500 light years, making the average dimensions about 0.378 pc. across.
The Owl Nebula is a starburst ("planetary") nebula approximately 2,030 light years away in the northern constellation Ursa 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.
Messier 110, or M110, also known as NGC 205, is a dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy in the Local Group.
Herbig–Haro (HH) objects are bright patches of nebulosity associated with newborn stars. They are formed when narrow jets of partially ionised gas ejected by stars collide with nearby clouds of gas and dust at several hundred kilometres per second. Herbig–Haro objects are commonly found in star-forming regions, and several are often seen around a single star, aligned with its rotational axis. Most of them lie within about one parsec of the source, although some have been observed several parsecs away. HH objects are transient phenomena that last around a few tens of thousands of years. They can change visibly over timescales of a few years as they move rapidly away from their parent star into the gas clouds of interstellar space. Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as parts of the nebula fade while others brighten as they collide with the clumpy material of the interstellar medium.
NGC 1999 is a dust-filled bright nebula with a vast hole of empty space represented by a black patch of sky, as can be seen in the photograph. It is a reflection nebula, and shines from the light of the variable star V380 Orionis.
The Orion Molecular Cloud Complex is a star forming region with stellar ages ranging up to 12 Myr. Two giant molecular clouds are a part of it, Orion A and Orion B. The stars currently forming within the Complex are located within these clouds. A number of other somewhat older stars no longer associated with the molecular gas are also part of the Complex, most notably the Orion's Belt, as well as the dispersed population north of it. Near the head of Orion there is also a population of young stars that is centered on Meissa. The Complex is between 1 000 and 1 400 light-years away, and hundreds of light-years across.
NGC 2023 is an emission and reflection nebula in the equatorial constellation of Orion. It was discovered by the German-born astronomer William Herschel on 6 January 1785. This reflection nebula is one of the largest in the sky, with a size of 10 × 10 arcminutes. It is located at a distance of 1,300 ly (400 pc) from the Sun, and is positioned ~15′ to the northeast of the Horsehead Nebula.
NGC 1333 is a reflection nebula located in the northern constellation Perseus, positioned next to the southern constellation border with Taurus and Aries. It was first discovered by German astronomer Eduard Schönfeld in 1855. The nebula is visible as a hazy patch in a small telescope, while a larger aperture will show a pair of dark nebulae designated Barnard 1 and Barnard 2. It is associated with a dark cloud L1450. Estimates of the distance to this nebula range from 980–1,140 ly (300–350 pc).
Vela Molecular Ridge is a molecular cloud complex in the constellations Vela and Puppis. Radio 12CO observations of the region showed the ridge to be composed of several clouds, each with masses 100,000–1,000,000 M☉. This cloud complex lies on the sky in the direction of the Gum Nebula (foreground) and the Carina–Sagittarius Spiral Arm (background). The most important clouds in the region are identified by the letters A, B, C and D, and in fact belong to two different complexes: the clouds A, C and D are located at an average distance of about 700-1000 parsecs and are related to the OB association Vela R2, while cloud B is located at a greater distance, up to 2000 parsecs away, and is physically connected to the extended Vela OB1 association.
HD 259431 is a young stellar object in the constellation of Monoceros.
The Herbig-Haro objects HH 1/2 are the first such objects to be recognized as Herbig-Haro objects and were discovered by George Herbig and Guillermo Haro. They are located at a distance of about 1500 light-years in the constellation Orion near NGC 1999. HH 1/2 are among the brightest Herbig-Haro objects in the sky and consist of a pair of oppositely oriented bow shocks, separated by 2.5 arcminutes. The HH 1/2 pair were the first Herbig-Haro objects with detected proper motion and HH 2 was the first Herbig-Haro object to be detected in x-rays. Some of the structures in the Herbig-Haro Objects move with a speed of 400 km/s.
HH 24-26 is a molecular cloud and star-forming region containing the Herbig-Haro objects HH 24, HH 25 and HH 26. This region contains the highest concentration of astrophysical jets known anywhere in the sky. The molecular cloud is located about 1400 light-years away in the L1630 dark cloud, which is part of the Orion B molecular cloud in the constellation of Orion.
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