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Cygnus OB7
Cygnus OB7 is an OB association in the giant Cygnus molecular cloud complex, which also contains the star-forming regions Cygnus X, the North America Nebula and the Pelican Nebula. The Northern Coalsack Nebula of the Cygnus Rift lies in the foreground of this region. The molecular cloud has a large angular size The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ... of ~4° × 7°. References Cygnus (constellation) Stellar associations {{Star-cluster-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus (constellation)
Cygnus is a northern constellation on the plane of the Milky Way, deriving its name from the Latinized Greek word for swan. Cygnus is one of the most recognizable constellations of the northern summer and autumn, and it features a prominent asterism known as the Northern Cross (in contrast to the Southern Cross). Cygnus was among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. Cygnus contains Deneb (ذنب, translit. ''ḏanab,'' tail)one of the brightest stars in the night sky and the most distant first-magnitude staras its "tail star" and one corner of the Summer Triangle. It also has some notable X-ray sources and the giant stellar association of Cygnus OB2. Cygnus is also known as the Northern Cross. One of the stars of this association, NML Cygni, is one of the largest stars currently known. The constellation is also home to Cygnus X-1, a distant X-ray binary containing a supergiant and unseen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OB Association
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well as the internal kinematics of more distant galaxies. Measurement of the kinematics of stars in different subcomponents of the Milky Way including the thin disk, the thick disk, the bulge, and the stellar halo provides important information about the formation and evolutionary history of our Galaxy. Kinematic measurements can also identify exotic phenomena such as hypervelocity stars escaping from the Milky Way, which are interpreted as the result of gravitational encounters of binary stars with the supermassive black hole at the Galactic Center. Stellar kinematics is related to but distinct from the subject of stellar dynamics, which involves the theoretical study or modeling of the motions of stars under the influence of gravity. Ste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus Molecular Cloud Complex
Cygnus-X is a massive star formation region located in the constellation of Cygnus at a distance from the Sun of 1.4 kilo parsecs (4,600 light years). As it is located behind the Cygnus Rift and its light is heavily absorbed by the Milky Way's interstellar dust, it is better studied in other wavelengths of the electromagnetic spectrum that penetrate it such as the infrared. Physical properties As studies done with the help of the Spitzer Space Telescope have shown, Cygnus-X has a size of 200 parsecs and contains the largest number of massive protostars as well as the largest stellar association (Cygnus OB2, with up to 2,600 stars of spectral type OB and a mass of up to 105 solar masses) within a radius of 2 kiloparsecs of the Sun. It is also associated with one of the largest molecular clouds known, with a mass of 3 million solar masses. Its stellar population includes a large number of early-type stars as well as evolved massive stars such as luminous blue variable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus-X (star Complex)
Cygnus-X is a massive star formation region located in the constellation of Cygnus at a distance from the Sun of 1.4 kiloparsecs (4,600 light years). As it is located behind the Cygnus Rift and its light is heavily absorbed by the Milky Way's interstellar dust, it is better studied in other wavelengths of the electromagnetic spectrum that penetrate it such as the infrared. Physical properties As studies done with the help of the Spitzer Space Telescope have shown, Cygnus-X has a size of 200 parsecs and contains the largest number of massive protostars as well as the largest stellar association (Cygnus OB2, with up to 2,600 stars of spectral type OB and a mass of up to 105 solar masses) within a radius of 2 kiloparsecs of the Sun. It is also associated with one of the largest molecular clouds known, with a mass of 3 million solar masses. Its stellar population includes a large number of early-type stars as well as evolved massive stars such as luminous blue variable candidat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America Nebula
The North America Nebula (NGC 7000 or Caldwell 20) is an emission nebula in the constellation Cygnus, close to Deneb (the tail of the swan and its brightest star). The shape of the nebula resembles that of the continent of North America, complete with a prominent Gulf of Mexico. History On October 24, 1786, William Herschel observing from Slough, England, noted a “faint milky nebulosity scattered over this space, in some places pretty bright.” The most prominent region was catalogued by his son John Herschel on August 21, 1829. It was listed in the New General Catalogue as NGC 7000, where it is described as a "faint, most extremely large, diffuse nebulosity.” In 1890, the pioneering German astrophotographer Max Wolf noticed this nebula's characteristic shape on a long-exposure photograph, and dubbed it the North America Nebula. In his study of nebulae on the Palomar Sky Survey plates in 1959, American astronomer Stewart Sharpless realised that the North America N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelican Nebula
The Pelican Nebula (also known as IC 5070 and IC 5067) is an H II region associated with the North America Nebula in the constellation Cygnus. The gaseous contortions of this emission nebula bear a resemblance to a pelican, giving rise to its name. The Pelican Nebula is located nearby first magnitude star Deneb, and is divided from its more prominent neighbour, the North America Nebula, by a foreground molecular cloud filled with dark dust. Both are part of the larger H II region of Westerhout 40. The Pelican is much studied because it has a particularly active mix of star formation and evolving gas clouds. The light from young energetic stars is slowly transforming cold gas to hot and causing an ionization front gradually to advance outward. Particularly dense filaments of cold gas are seen to still remain, and among these are found two jets emitted from the Herbig–Haro object 555. Millions of years from now this nebula might no longer be known as the Pelican, as the balance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Coalsack Nebula
In astronomy, the Great Rift (sometimes called the Dark Rift or less commonly the Dark River) is a dark band caused by interstellar clouds of cosmic dust that significantly obscure (extinguish) the center and most radial sectors of the Milky Way galaxy from Earth's perspective. In dark, clear night skies, the rift appears as clear as the bright bulge of stars around the Galactic Center does to the naked eye or binoculars. The rift is largely between the Solar System (which is close to the inner edge of the Orion Arm) and the next arm, inward, the Sagittarius Arm. The clouds are an obstruction to millions of the galaxy's stars detected at visible wavelengths, which compose a bright hazy band appearing 30° wide and arching through the night sky. The clouds within our radial sector of the galaxy span about from Earth. The clouds are estimated to contain about 1 million solar masses of plasma and dust. Properties To the naked eye, the Great Rift appears as a dark lane that d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus Rift
In astronomy, the Great Rift (sometimes called the Dark Rift or less commonly the Dark River) is a dark band caused by interstellar clouds of cosmic dust that significantly obscure ( extinguish) the center and most radial sectors of the Milky Way galaxy from Earth's perspective. In dark, clear night skies, the rift appears as clear as the bright bulge of stars around the Galactic Center does to the naked eye or binoculars. The rift is largely between the Solar System (which is close to the inner edge of the Orion Arm) and the next arm, inward, the Sagittarius Arm. The clouds are an obstruction to millions of the galaxy's stars detected at visible wavelengths, which compose a bright hazy band appearing 30° wide and arching through the night sky. The clouds within our radial sector of the galaxy span about from Earth. The clouds are estimated to contain about 1 million solar masses of plasma and dust. Properties To the naked eye, the Great Rift appears as a dark lane that d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Size
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is the angular aperture (of a lens). The angular diameter can alternatively be thought of as the angular displacement through which an eye or camera must rotate to look from one side of an apparent circle to the opposite side. Humans can resolve with their naked eyes diameters of up to about 1 arcminute (approximately 0.017° or 0.0003 radians). This corresponds to 0.3 m at a 1 km distance, or to perceiving Venus as a disk under optimal conditions. Formula The angular diameter of a circle whose plane is perpendicular to the displacement vector between the point of view and the center of said circle can be calculated using the formula :\delta = 2\arctan \left(\frac\right), in which \delta is the angular diameter, and d i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
