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SR 12 (star)
SR 12 (also known as V2247 Oph) is a weak-line T-Tauri binary that has a planetary-mass companion with a detected accretion disk. The binary SR 12 was discovered by Otto Struve and Mogens Rudkjøbing in 1949 as an emission-line star with a spectral type of M. The first letters of their names were used to name the star, together with the star number in their catalog. It was also observed as an x-ray source with the Einstein Observatory, having the designation ROX 21. The binary was discovered with the help of lunar occultations and speckle interferometry in 1987. The binary is located in the ''ρ'' Ophiuchi star-forming region and is a weak-line T-Tauri binary, meaning it still accretes gaseous material from a circumstellar disk. There are differences in spectral type classifications of the individual stars. A K4/M2.5 binary was suggested, as well as a M3+M8 binary. The binary is separated by about 0.21 arcseconds, which corresponds to a separation of 24 AU. Speckle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SR 12 C
SR or sr may refer to: Arts and entertainment * ''Science Reporter'', a magazine * '' "Sr."'', a 2022 film featuring Roberts Downey Jr. and Sr. Businesses and organizations Politics * Socialist Revolutionary Party, Russia, 1902–1941 * A Just Russia (''Spravedlivaya Rossiya''), a political party formed in 2006 Transport * Southern Railway (UK) * Southern Railway (U.S.) * Swissair (IATA airline code SR) * Southern Railway zone, India * SR Corporation, a South Korean rail operator Other businesses and organizations * Sørvágs Róðrarfelag, a Faroese rowing association * Saarländischer Rundfunk, a German broadcaster * Sveriges Radio, a Swedish broadcaster Honorifics * Senior (Sr.), a generational title suffix to a man's name * Religious sister (Sr.), in Catholicism Places * Slovak Republic (), the official name of Slovakia * Suriname (ISO 3166-1 country code SR) * West Sulawesi (ISO 3166-2:ID province code SR), a province of Indonesia Science and technology Biology and med ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Astrophysical Research Telescope
The Southern Astrophysical Research (SOAR) telescope is a modern optical and near-infrared telescope located on Cerro Pachón, Chile at elevation. It was commissioned in 2003, and is operated by a consortium including the countries of Brazil and Chile, Michigan State University, the Cerro Tololo Inter-American Observatory (CTIO) (part of the National Optical Astronomy Observatory, NOAO), and the University of North Carolina at Chapel Hill. Partners have guaranteed shares varying from 10 to 30 percent of the observing time. The telescope uses active optics on its primary and secondary mirrors to attain median image quality 0.7 arcsec at a wavelength of 500 nm. Multiple instruments are available on standby, mounted at unusually high weight-capacity Nasmyth foci and two lower capacity bent- Cassegrain foci. Switching is accomplished within a few minutes by rotating the 45° tertiary mirror. The pointing of this mirror is adjusted at high speed to prevent image blur from vibrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen-alpha
Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. Balmer series According to the Bohr model of the atom, electrons exist in quantized energy levels surrounding the atom's nucleus. These energy levels are described by the principal quantum number ''n'' = 1, 2, 3, ... . Electrons may only exist in these states, and may only transit between these states. The set of transitions from ''n'' ≥ 3 to ''n'' = 2 is called the Balmer series and its members are named sequentially by Greek letters: *''n'' = 3 to ''n'' = 2 is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Energy Distribution
A spectral energy distribution (SED) is a plot of energy versus frequency or wavelength of light (not to be confused with a 'spectrum' of flux density vs frequency or wavelength). It is used in many branches of astronomy to characterize astronomical sources. For example, in radio astronomy they are used to show the emission from synchrotron radiation, free-free emission and other emission mechanisms. In infrared astronomy, SEDs can be used to classify young stellar objects. Detector for spectral energy distribution The count rates observed from a given astronomical radiation source have no simple relationship to the flux from that source, such as might be incident at the top of the Earth's atmosphere. This lack of a simple relationship is due in no small part to the complex properties of radiation detectors. These detector properties can be divided into *those that merely attenuate the beam, including *#residual atmosphere between source and detector, *#absorption in the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L Dwarf
An object with the spectral type L (also called L-dwarf) can be either a low-mass star, a brown dwarf or a young rogue planet, free-floating planetary-mass object. If a young exoplanet or planetary-mass companion is detected via direct imaging, it can also have an L spectral type, such as Kappa Andromedae b. Spectral characteristics Before 2MASS there were only six known objects with a spectral type later than M9.5V. With the discovery of 20 new late-type objects it was necessary to define the L-type and T-dwarf, T-type spectral types. Davy Kirkpatrick, Kirkpatrick et al. defined the two spectral types in 1999. In these L-dwarfs the metallic Oxide, oxides (Titanium(II) oxide, TiO, Vanadium(II) oxide, VO), which are present in red dwarfs, late M-dwarfs, are replaced with metallic Hydride, hydrides (e.g. Chromium(I) hydride, CrH, Iron(I) hydride, FeH) and neutral alkali metal, alkali metals (e.g. potassium, K, rubidium, Rb, cesium, Cs). The transition between L- and T-dwarfs is de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Gravity
The surface gravity, ''g'', of an astronomical object is the gravitational acceleration experienced at its surface at the equator, including the effects of rotation. The surface gravity may be thought of as the acceleration due to gravity experienced by a hypothetical test particle which is very close to the object's surface and which, in order not to disturb the system, has negligible mass. For objects where the surface is deep in the atmosphere and the radius not known, the surface gravity is given at the 1 bar pressure level in the atmosphere. Surface gravity is measured in units of acceleration, which, in the SI system, are meters per second squared. It may also be expressed as a multiple of the Earth's standard surface gravity, which is equal to In astrophysics, the surface gravity may be expressed as , which is obtained by first expressing the gravity in cgs units, where the unit of acceleration and surface gravity is centimeters per second squared (cm/s2), and then t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), 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 cool ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near Infrared Camera And Multi-Object Spectrometer
The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is a Measuring instrument, scientific instrument for infrared astronomy, installed on the Hubble Space Telescope (HST), operating from 1997 to 1999, and from 2002 to 2008. Images produced by NICMOS contain data from the near-infrared part of the light spectrum. NICMOS was conceived and designed by the NICMOS Instrument Definition Team centered at Steward Observatory, University of Arizona, USA. NICMOS is an imager and Multi-Object Spectrometer, multi-object spectrometer built by Ball Aerospace & Technologies Corp. that allows the HST to observe infrared light, with wavelengths between 0.8 and 2.4 micrometers, providing imaging and slitless spectrophotometric capabilities. NICMOS contains three near-infrared detectors in three optical channels providing high (~ 0.1 arcsecond) resolution, coronagraphic and polarimetric imaging, and slitless spectroscopy in 11-, 19-, and 52-arcsecond square fields of view. Each optical ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very Large Telescope
The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with a primary mirror that measures in diameter. These optical telescopes, named ''Antu'', ''Kueyen'', ''Melipal'', and ''Yepun'' (all words for astronomical objects in the Mapuche language), are generally used separately but can be combined to achieve a very high angular resolution. The VLT array is also complemented by four movable Auxiliary Telescopes (ATs) with apertures. The VLT is capable of observing both visible and infrared wavelengths. Each individual telescope can detect objects that are roughly four billion times fainter than what can be seen with the naked eye. When all the telescopes are combined, the facility can achieve an angular resolution of approximately 0.002 arcsecond. In single telescope mode, the angular resol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hubble Space Telescope
The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most versatile, renowned as a vital research tool and as a public relations boon for astronomy. The Hubble Space Telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories program, 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 spectrum, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of atmosphere of Earth, Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subaru Telescope
is the telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades. It had the largest monolithic primary mirror in the world from its commissioning until the Large Binocular Telescope opened in 2005. Overview The Subaru Telescope is a Ritchey-Chretien reflecting telescope. Instruments can be mounted at a Cassegrain focus below the primary mirror; at either of two Nasmyth focal points in enclosures on the sides of the telescope mount, to which light can be directed with a tertiary mirror; or at the prime focus in lieu of a secondary mirror, an arrangement rare on large telescopes, to provide a wide field of view suited to deep wide-field surveys. In 1984, the University of Tokyo formed an engineering working group to develop and study the concept of a telescope. In 1985, the astronomy committee of Japan's science council gave top priority to the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South African Astronomical Observatory
The South African Astronomical Observatory (SAAO) is the national centre for optical and infrared astronomy in South Africa. It was established in 1972. The observatory is run by the National Research Foundation of South Africa. The facility's function is to conduct research in astronomy and astrophysics. The primary telescopes are located in Sutherland, which is from Observatory, Cape Town, where the headquarters is located. The SAAO has links worldwide for scientific and technological collaboration. Instrumental contributions from the South African Astronomical Observatory include the development of a spherical aberration corrector and the Southern African Large Telescope (SALT). The Noon Gun on Cape Town's Signal Hill is fired remotely by a time signal from the Observatory. History The history of the SAAO began when the Royal Observatory at the Cape of Good Hope was founded in 1820, the first scientific institution in Africa. Construction of the main buildings was c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
