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Iota Coronae Borealis
Iota Coronae Borealis, Latinized from ι Coronae Borealis, is a binary star system in the constellation Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of is 4.96. Based upon an annual parallax shift of 10.46 mas as seen from the Earth, it is located about 312 light years from the Sun. This is a single-lined spectroscopic binary with an orbital period of 35.5 days and an eccentricity of 0.56. The visible member, component A, has a stellar classification of , indicating it is a chemically peculiar mercury-manganese star with narrow absorption lines. The secondary member, component B, appears to be an A-type star An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1 .... References {{DEFAULTSORT:Iota Coronae Bore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a Astronomical object, celestial body, as they are subject to Perturbation (astronomy), perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or Perihelion and aphelion, aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopic Binary
A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit (astronomy), transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stella ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Durchmusterung Objects
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, compiled by the Bonn Observatory in Germany from 1859 to 1903. The name comes from ('run-through examination'), a German word used for a systematic survey of objects or data. The term has sometimes been used for other astronomical surveys, including not only stars, but also the search for other celestial objects. Special tasks include celestial scanning in electromagnetic wavelengths shorter or longer than visible light waves. Original catalog The 44 years of work on the Bonner Durchmusterung (abbreviated BD), initiated by Friedrich Argelander and largely carried out by his assistants, resulted in a catalogue of the positions and apparent magnitudes of approximately 325,000 stars to apparent magnitude 9–10. The catalogue was accompanied by charts plotting the positions of the stars, and was the basis for the ''Astronomische Gesellschaft Katalog'' (AGK) and ''Smithsonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Objects
Bayer AG (, commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of business include pharmaceuticals; consumer healthcare products, agricultural chemicals, seeds and biotechnology products. The company is a component of the Euro Stoxx 50 stock market index. Bayer was founded in 1863 in Barmen as a partnership between dye salesman Friedrich Bayer and dyer Friedrich Weskott. As was common in this era, the company was established as a dyestuffs producer. The versatility of aniline chemistry led Bayer to expand their business into other areas, and in 1899 Bayer launched the compound acetylsalicylic acid under the trademarked name Aspirin. In 1904 Bayer received a trademark for the "Bayer Cross" logo, which was subsequently stamped onto each aspirin tablet, creating an iconic product that is still sold by Bayer. Other commonly known produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopic Binaries
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury-manganese Stars
A mercury-manganese star (also HgMn star) is a type of chemically peculiar star with a prominent spectral line at 398.4 nm, due to absorption from ionized mercury. These stars are of spectral type B8, B9, or A0, corresponding to surface temperatures between about 10,000 and 15,000 K, with two distinctive characteristics: * An atmospheric excess of elements like phosphorus, manganese, gallium, strontium, yttrium, zirconium, platinum and mercury. * A lack of a strong dipole magnetic field. Their rotation is relatively slow, and as a consequence their atmosphere is relatively calm. It is thought, but has not been proven, that some types of atoms sink under the force of gravity, while others are lifted towards the exterior of the star by radiation pressure Radiation pressure is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. This includes the momentum of light or electromagnetic radiation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Giants
A type or type A may refer to: * A-type asteroid, a type of relatively uncommon inner-belt asteroids * A type blood, a type in the ABO blood group system * A-type inclusion, a type of cell inclusion * A-type potassium channel, a type of voltage-gated potassium channel * A type proanthocyanidin, a specific type of flavonoids * A-type star, a class of stars * Type A Dolby Noise Reduction, a type of Dolby noise-reduction system * Type A climate, a type in the Köppen climate classification * Type A flu, a type of influenza virus * Type A evaluation of uncertainty, an uncertainty in measurement that can be inferred, for example, from repeated measurement * Type A (label), a music label that for example produced the 2004 album '' What Doesn't Kill You...'' by Candiria * Type A personality, a personality type in the Type A and Type B personality theory * Type A submarine, a class of submarines in the Imperial Japanese Navy which served during the Second World War * Hemophilia type A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy And Astrophysics
''Astronomy & Astrophysics'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. The journal is run by a Board of Directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The journal is published by EDP Sciences and the editor-in-chief is . History Origins ''Astronomy and Astrophysics'' (A&A) was created as an answer to the publishing scenario found in Europe in the 1960s. At that time, multiple journals were being published in several countries around the continent. These journals usually had a limited number of subscribers, and published articles in languages other than English, resulting in a small number of citations compared to American and British journals. Starting in 1963, conversations between astronomers from European countries assessed the need for a common astronomical journal. On 8 April 1968, leading astronomers from Belgium, Denmark, Fran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Star
An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1.4 and 2.1 solar masses () and have surface temperatures between 7,600 and 10,000 K. Bright and nearby examples are Altair (A7 V), Sirius A (A1 V), and Vega (A0 V). A-type stars do not have convective zones and thus are not expected to harbor magnetic dynamos. As a consequence, because they do not have strong stellar winds, they lack a means to generate X-ray emissions. In July 2019, astronomers reported finding an A-type star, S5-HVS1, traveling , faster than any other star detected so far. The star is in the Grus (or Crane) constellation in the southern sky, about 29,000 light-years from Earth, and may have been ejected out of the Milky Way after interacting with Sagittarius A*, the supermassive black hole at the center of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption Line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same frequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury-manganese Star
A mercury-manganese star (also HgMn star) is a type of chemically peculiar star with a prominent spectral line at 398.4 nm, due to absorption from ionized mercury. These stars are of spectral type B8, B9, or A0, corresponding to surface temperatures between about 10,000 and 15,000 K, with two distinctive characteristics: * An atmospheric excess of elements like phosphorus, manganese, gallium, strontium, yttrium, zirconium, platinum and mercury. * A lack of a strong dipole magnetic field. Their rotation is relatively slow, and as a consequence their atmosphere is relatively calm. It is thought, but has not been proven, that some types of atoms sink under the force of gravity, while others are lifted towards the exterior of the star by radiation pressure Radiation pressure is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. This includes the momentum of light or electromagnetic radiation of any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemically Peculiar Star
In astrophysics, chemically peculiar stars (CP stars) are stars with distinctly unusual Metallicity, metal abundances, at least in their surface layers. Classification Chemically peculiar stars are common among hot main-sequence (hydrogen-burning) stars. These hot peculiar stars have been divided into 4 main classes on the basis of their spectra, although two classification systems are sometimes used: * non-magnetic metallic-lined star, metallic-lined (Am, CP1) * Ap and Bp stars, magnetic (Ap, CP2) * non-magnetic mercury-manganese star, mercury-manganese (HgMn, CP3) * Helium-weak star, helium-weak (He-weak, CP4). The class names provide a good idea of the peculiarities that set them apart from other stars on or near the main sequence. The Am stars (CP1 stars) show weak lines of singly ionized Calcium, Ca and/or Scandium, Sc, but show enhanced abundances of heavy metals. They also tend to be slow rotators and have an effective temperature between 7000 and . The Ap stars (CP2 sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
