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36 Lyncis
36 Lyncis is a solitary variable star located around 620 light years away from the Sun in the northern constellation of Lynx. It has the variable star designation of EI Lyncis, while ''36 Lyncis'' is the Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.30. It is moving further away from the Earth with a heliocentric radial velocity of 21 km/s. This is a magnetic, helium-weak Bp star with a stellar classification of B9IVpHgMn, although the spectral peculiarities have led to alternate classifications such as B8 IIImnp. It is sometimes classified as a mercury-manganese star. It is also an 'sn' star, displaying a spectrum with generally sharp lines for most elements in combination with broad, diffuse lines of helium. 36 Lyncis has been classified as an SX Arietis variable with an amplitude of 0.03 in visual magnitude and a rotationally-modulated period of 3.834 days. The ... [...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 frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flamsteed Objects
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas Coelestis'', both published posthumously. He also made the first recorded observations of Uranus, although he mistakenly catalogued it as a star, and he laid the foundation stone for the Royal Greenwich Observatory. Life Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed and his first wife, Mary Spadman. He was educated at the free school of Derby and at Derby School, in St Peter's Churchyard, Derby, near where his father carried on a malting business. At that time, most masters of the school were Puritans. Flamsteed had a solid knowledge of Latin, essential for reading the scientific literature of the day, and a love of history, leaving the school in May 1662.Birks, John L. (1999) ''John Flamsteed, th ... [...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 '' Smith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SX Arietis Variables
SX Arietis variables are a class of variable stars. They are generally B-type main sequence stars of spectral types B0p to B9p— high-temperature analogues of Alpha2 Canum Venaticorum variables—and exhibit strong magnetic fields and intense He I and Si III spectral lines. They have brightness fluctuations of approximately 0.1 magnitudes with periods of about one day. The prototype of this class is 56 Arietis, which bears the variable star designation In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constel ... ''SX Arietis''. List The following list contains selected SX Arietis variable that are of interest to amateur or professional astronomy. Unless otherwise noted, the given magnitudes are in the V-band. Notes References Samus N.N., Durlevich O.V., et al. ''Combined G ... [...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 Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, an ... sink under the force of gravity, while others are lifted towards the exterior of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium-weak Stars
Helium-weak stars are chemically peculiar stars which have a weak helium lines for their spectral type. Their helium lines place them in a later (i.e. cooler) spectral type then their hydrogen lines. List of helium-weak stars This is a non-extensive list of helium-weak stars. Helium-strong star A related class of stars have anomalously strong helium lines in their spectra, and are known as helium-strong stars. See also * Helium star * Extreme helium star An extreme helium star (abbreviated EHe) is a low-mass supergiant that is almost devoid of hydrogen, the most common chemical element of the Universe. Since there are no known conditions where stars devoid of hydrogen can be formed from molecular c ... References Star types {{stellar-astronomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-type Subgiants
B type or Type B may refer to: Astronomy * B-type asteroid, a type of relatively uncommon type of carbonaceous asteroid * B-type giant, a type of blue giant star * B-type star, a type of star Biology * B type blood, a type in the ABO blood group system * B type inclusion, a type of inclusions in cells infected with poxvirus * B-type natriuretic peptide, a type of brain natriuretic peptides * B type proanthocyanidin, a specific type of flavanoids * Type B evaluation of uncertainty, an uncertainty in measurement inferred from scientific judgement or other information concerning the possible values of the quantity * Type B personality, a type in the Type A and Type B personality theory Others * B-type warbird, a type of Romulan starship * Type B videotape, an open-reel videotape format * Curtiss-built B-type, a type of B class blimp * LGOC B-type, a model of double-decker bus that was introduced in London on 1910 * Mann Egerton Type B, a 1910s British maritime patrol airc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association Of Variable Star Observers
The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization, founded in 1911, focused on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. The AAVSO creates records that establish light curves depicting the variation in brightness of a star over time, and makes them available to professional astronomers, researchers, and educators. Since professional astronomers do not have the time or the resources to monitor every variable star, astronomy is one of the few sciences where amateurs can make genuine contributions to scientific research. During 2011, the 100th year of the AAVSO's existence, the 20-millionth variable star observation was received into the database. The AAVSO International Database (AID) stores over 35 million observations as of 2019. The organization receives nearly 1,000,000 observations annually from around 2,000 professional and amateur observers and is q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, including greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not stra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Composition of the Sun The Sun is composed primari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity Of The Sun
The solar luminosity (), is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This does not include the solar neutrino luminosity, which would add , or , i.e. a total of (the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0.59 MeV, i.e. 2.27%; the Sun emits photons and as many neutrinos each second, of which per m2 reach the Earth each second). The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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