|
Cygnus X (star Complex)
Cygnus-X is a massive star formation region located in the constellation of Cygnus (constellation), Cygnus at a distance from the Sun of 1.4 kiloparsecs (4,600 light-year, light years). It has a dimension of 7° x 7°, which translates into around 170x170 pc (560x560 ly), at a distance of 1.4 kpc. As it is located behind the Cygnus Rift and its light Extinction (astronomy), 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 Stellar classification, 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 molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus OB2
Cygnus OB2 is an OB association that is home to some of the most massive and most luminous stars known, including suspected Luminous blue variable Cyg OB2 #12. It also includes one of the largest known stars, NML Cygni. The region is embedded within a wider one of star formation known as Cygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The region is approximately 1,570 parsecs from Earth in the constellation of Cygnus. The young cluster is one of the largest known and the largest in the northern hemisphere with some authors formerly classifying it as a young globular cluster similar to those in the Large Magellanic Cloud. Today, however, it is considered a massive, low-density stellar association. Although it is over ten times more massive than the Orion Nebula, which is easily seen with the naked eye, Cygnus OB2 is hidden behind a massive dust cloud known as the Cygnus Rift, which obscures many of the stars in it. This means that de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orion Molecular Cloud Complex
The Orion molecular cloud complex (or, simply, the Orion complex) is a star-forming region with stellar ages ranging up to 12 Myr. Two Molecular cloud#Giant molecular clouds, 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 (Orion OB1b), as well as the dispersed population north of it (Orion OB1a). 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. The Orion complex is one of the most active regions of nearby star formation, stellar formation visible in the night sky, and is home to both protoplanetary discs and very young stars. Much of it is bright in infrared wavelengths due to the heat-intensive process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Supergiant Star
A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They are usually considered to be those with luminosity class I and spectral class B9 or earlier, although sometimes A-class supergiants are also deemed blue supergiants. Blue supergiants are found towards the top left of the Hertzsprung–Russell diagram, above and to the right of the main sequence. By analogy to the red giant branch for low-mass stars, this region is also called the blue giant branch. They are larger than the Sun but smaller than a red supergiant, with surface temperatures of 10,000–50,000 K and luminosities from about 10,000 to a million times that of the Sun. They are most often an evolutionary phase between high-mass, hydrogen-fusing main-sequence stars and helium-fusing red supergiants, although new research suggests they could be the result of stellar mergers. The majority of supergiants are also blue (B-type) supergiants; blue supergiants from classes O9.5 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BD+40°4210
BD+40°4210 is a hot luminous supergiant star located in the constellation Cygnus. It is a member of the Cygnus OB2 association and a candidate luminous blue variable. Features BD+40°4210 is heavily reddened and extinguished by the interstellar dust of the Milky Way and little studied. It has turned out to be one of the most luminous stars of the Cygnus OB2 association, with an absolute magnitude of −7.66 and a bolometric luminosity more than 600,000 times that of the Sun. It has been assigned a B1III spectral classification, but with peculiarities including unusually shallow lines and broad emission. Despite the giant luminosity class, the luminosity appears to be extremely high, placing it on or near the S Doradus instability strip occupied by quiescent luminous blue variables. Its brightness varies by less than 0.1 magnitudes on a timescale around 100 days. BD+40°4210 is located at a projected 4.8 parsec The parsec (symbol: pc) is a unit of length used t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus OB9
Cygnus OB9 is an OB association in Cygnus. It is near to the Cygnus OB2 association. The region is embedded within a wider one of star formation known as Cygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The region is approximately 5000 light years from Earth in the constellation of Cygnus. Although Cygnus OB9 has many O and B type stars, Cygnus OB9 is also hidden behind a massive dust cloud known as the Cygnus Rift like Cygnus OB2. See also * List of most massive stars This is a list of the most massive stars that have been discovered, in solar mass units (). Uncertainties and caveats Most of the masses listed below are contested and, being the subject of current research, remain under review and subject to con ... References Stellar associations Cygnus (constellation) Star-forming regions {{star-cluster-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
O-type Star
An O-type star is a hot, blue star of spectral type O in the Yerkes classification system employed by astronomers. They have surface temperatures in excess of 30,000 kelvins (K). Stars of this type have strong absorption lines of ionised helium, strong lines of other ionised elements, and hydrogen and neutral helium lines weaker than spectral type B. Stars of this type are very rare, but because they are very bright, they can be seen at great distances; out of the 90 brightest stars as seen from Earth, 4 are type O. Due to their high mass, O-type stars end their lives rather quickly in violent supernova explosions, resulting in black holes or neutron stars. Most of these stars are young massive main sequence, giant, or supergiant stars, but also some central stars of planetary nebulae, old low-mass stars near the end of their lives, which typically have O-like spectra. O-type stars are typically found in regions of active star formation, such as the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supergiant Star
Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram, with absolute magnitude, absolute visual magnitudes between about −3 and −8. The temperatures of supergiant stars range from about 3,400 K to over 20,000 K. Definition The title ''supergiant'', as applied to a star, does not have a single concrete definition. The term ''giant star'' was first coined by Hertzsprung, Ejnar, Hertzsprung when it became apparent that the majority of stars fell into two distinct regions of the Hertzsprung–Russell diagram. One region contained larger and more luminous stars of Stellar classification, spectral types A to M, which received the name ''giant''. Subsequently, as they lacked any measurable parallax, it became apparent that some of these stars were significantly larger and more luminous than the bulk, and the term ''super-giant'' arose, quickly adopted as ''supergiant''. Supergiants wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolf–Rayet Star
Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectroscopy, spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface enhancement of Stellar nucleosynthesis, heavy elements, depletion of hydrogen, and strong stellar winds. The Effective temperature, surface temperatures of known Wolf–Rayet stars range from 20,000 Kelvin (unit), K to around 210,000 Kelvin (unit), K, hotter than almost all other kinds of stars. They were previously called W-type stars referring to their Stellar classification, spectral classification. Classic (or population I) Wolf–Rayet stars are Stellar evolution, evolved, massive stars that have completely lost their outer hydrogen and are nuclear fusion, fusing helium or heavier elements in the core. A subset of the population I WR stars show hydrogen lines in their spectra and are known as WNh stars; the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminous Blue Variable
Luminous blue variables (LBVs) are rare, massive, evolved stars that show unpredictable and sometimes dramatic variations in their spectra and brightness. They are also known as S Doradus variables after S Doradus, one of the brightest stars of the Large Magellanic Cloud. Discovery and history The LBV stars P Cygni and Eta Carinae, η Carinae have been known as unusual variables since the 17th century, but their true nature was not fully understood until late in the 20th century. In 1922 John Charles Duncan published the first three variable stars ever detected in an external galaxy, variables 1, 2, and 3, in the Triangulum Galaxy (M33). These were followed up by Edwin Hubble with three more in 1926: A, B, and C in M33. Then in 1929 Hubble added a list of variables detected in Messier 31, M31. Of these, Var A, Var B, Var C, and Var 2 in M33 and Var 19 in M31 were followed up with a detailed study by Hubble and Allan Sandage in 1953. Var 1 in M33 was excluded as being too faint a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early-type Star
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the coolest (''M'' type). Each letter class is then subdivided ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
