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NGC 1333
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 (Barnard 205). Estimates of the distance to this nebula range from . This nebula is in the western part of the Perseus molecular cloud and is a young region of very active star formation, being one of the best-studied objects of its type. It contains a fairly typical hierarchy of star clusters that are still embedded in the molecular cloud in which they formed, which are split into two main sub-groups to the north and south. Most of the infrared emission is happening in the southern part of the nebula. A significant portion of the stars seen in the infrared are in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pre-main-sequence Star
A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence. Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of interstellar dust and gas. After the protostar blows away this envelope, it is optically visible, and appears on the stellar birthline in the Hertzsprung-Russell diagram. At this point, the star has acquired nearly all of its mass but has not yet started hydrogen burning (i.e. nuclear fusion of hydrogen). The star then contracts, its internal temperature rising until it begins hydrogen burning on the zero age main sequence. This period of contraction is the pre-main sequence stage. An observed PMS object can either be a T Tauri star, if it has fewer than 2 solar masses (), or else a Herbig Ae/Be star, if it has 2 to 8 . Yet more massive stars have no pre-main-sequence stage because they contract too quickly as protostars. By the time th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection Nebulae
Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, reflection from a smooth surface *** Mirror image, a reflection in a mirror or in water ** Signal reflection, in signal transmission * Elastic scattering, a process in nuclear and particle physics * Reflection nebula, a nebula that is extended and has no boundaries * Reflection seismology or seismic reflection, a method of exploration geophysics Mathematics * Reflection principle, in set theory * Point reflection, a reflection across a point * Reflection (mathematics), a transformation of a space * Reflection formula, a relation in a function * Reflective subcategory, in category theory Computing * Reflection (computer graphics), simulation of reflective surfaces * Reflection (computer programming), a program that accesses or modifies its own code * Reflection, terminal emulation software by Attachmate Arts and entertainment Film and televisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barnard 204
Barnard is a version of the surname Bernard, which is a French and West Germanic masculine given name and surname. The surname means as tough as a bear, Bar(Bear)+nard/hard(hardy/tough) __NOTOC__ People Some of the people bearing the surname Barnard in England are thought to have arrived after the time of the Norman Conquest (1066), Changing their surnames from Bernard to Barnard. Some of whom, it has been suggested, can be traced back to Hugo Bernard. Some of the Barnard family in England may have been Huguenots who fled from the Atlantic coast region of France ''circa'' 1685 (the time of the revocation of the edict of Nantes) or earlier than that date. By contrast, the Barnard family in Holland (the western provinces of the Netherlands) can be definitively traced back to ''circa'' 1751 (Izaak Barnard) of Scheveningen.The surname Barnard is also found in South Africa among the Afrikaner community. An example of this is Christiaan Barnard, A South African Cardiac Surgeon w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barnard 203
The dark nebula Barnard 203 or Lynds 1448 is located about one Degree (angle), degree southwest of NGC 1333 in the Perseus molecular cloud, at a distance of about 800 light-years. Three Infrared astronomy, infrared sources were observed in this region by IRAS, called IRS 1, IRS 2 and IRS 3. The region also contains multiple Herbig–Haro object, Herbig-Haro objects, including HH 193–197, which are driven by the protostars in this region. The young stellar object population The source IRS 1 is a class I young stellar object and a binary. IRS 1 is more evolved than most of the protostars in this region and less well-studied. The source IRS 2 is a binary that is very young (class 0 young stellar object), surrounded by a rotating disk and the system shows a bipolar outflow signature. The system has an hourglass shaped magnetic field that is aligned with the bipolar outflow. Towards the east is the source L1448-IRS2E, IRS 2E, a source between a pre-stellar core and a protostar. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Lemmon Observatory
Mount Lemmon Observatory (MLO), also known as the Mount Lemmon Infrared Observatory, is an astronomical observatory located on Mount Lemmon in the Santa Catalina Mountains approximately northeast of Tucson, Arizona (US). The site in the Coronado National Forest is used with special permission from the U.S. Forest Service by the University of Arizona's Steward Observatory, and contains a number of independently managed telescopes. History The MLO site was first developed in 1954 as Mount Lemmon Air Force Station, a radar installation of the Air Defense Command. Upon transfer to the Steward Observatory 1970, the site was converted to an infrared observatory. Until 2003, a radar tower operated from Fort Huachuca was used to track launches from the White Sands Missile Range in New Mexico and Vandenberg Air Force Base in California. Telescopes Below are the 8 telescopes currently operating at the observatory. * The Steward Observatory Telescope is a Cassegrain reflector used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hubble Space Telescope
The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft. Hubble features a mirror, and its five main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detaile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rho Ophiuchi Cloud Complex
The Rho Ophiuchi cloud complex is a complex of interstellar clouds with different nebulae, particularly dark nebulae which is centered 1° south of the star ρ Ophiuchi, which it among others extends to, of the constellation Ophiuchus. At an estimated distance of , or 460 light years, it is one of the closest star-forming regions to the Solar System. Cloud complex This cloud covers an angular area of on the celestial sphere. It consists of two major regions of dense gas and dust. The first contains a star-forming cloud (L1688) and two filaments (L1709 and L1755), while the second has a star-forming region (L1689) and a filament (L1712–L1729). These filaments extend up to 10–17.5 parsecs in length and can be as narrow as 0.24 parsecs in width. The large extensions of the complex are also called ''Dark River'' clouds (or ''Rho Ophiuchi Streamers'') and are identified as Barnard 44 and 45. Some of the structures within the complex appear to be the result of a shock front pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Dwarf
Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most massive gas giant planets and the least massive stars, approximately 13 to 80 times that of Jupiter (). However, they can fuse deuterium ( 2H), and the most massive ones (> ) can fuse lithium ( 7Li). Astronomers classify self-luminous objects by spectral class, a distinction intimately tied to the surface temperature, and brown dwarfs occupy types M, L, T, and Y. As brown dwarfs do not undergo stable hydrogen fusion, they cool down over time, progressively passing through later spectral types as they age. Despite their name, to the naked eye, brown dwarfs would appear in different colors depending on their temperature. The warmest ones are possibly orange or red, while cooler brown dwarfs would likely appear magenta or black to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbig–Haro Object
Herbig–Haro (HH) objects are bright patches of nebula, nebulosity associated with newborn stars. They are formed when narrow jets of partially plasma (physics), 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 formation#Stellar nurseries, star-forming regions, and several are often seen around a single star, aligned with its axis of rotation, rotational axis. Most of them lie within about one parsec (3.26 light-years) 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 (the interstellar medium or ISM). Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Young Stellar Object
Young stellar object (YSO) denotes a star in its early stage of evolution. This class consists of two groups of objects: protostars and pre-main-sequence stars. Classification by spectral energy distribution A star forms by accumulation of material that falls in to a protostar from a circumstellar disk or envelope. Material in the disk is cooler than the surface of the protostar, so it radiates at longer wavelengths of light producing excess infrared emission. As material in the disk is depleted, the infrared excess decreases. Thus, YSOs are usually classified into evolutionary stages based on the slope of their spectral energy distribution in the mid-infrared, using a scheme introduced by Lada (1987). He proposed three classes (I, II and III), based on the values of intervals of spectral index \alpha \,: \alpha=\frac. Here \lambda \, is wavelength, and F_\lambda is flux density. The \alpha \, is calculated in the wavelength interval of 2.2–20 m ( near- and mid-infrared reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Evolution
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star. Nuclear fusion powers a star for most of its existence. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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