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Sigma Draconis
Sigma Draconis is a single star in the northern constellation of Draco. It has the proper name Alsafi , while Sigma Draconis, which is latinised from σ Draconis and abbreviated Sig Dra or σ Dra, is the Bayer designation. It has an apparent visual magnitude of 4.7, which is bright enough to be faintly visible to the naked eye. Based on parallax measurements, this star is located at a distance of 18.8 light years from the Sun. It is receding from the Sun with a radial velocity of 26.8 km/s. Name ''σ Draconis'' ( Latinised to ''Sigma Draconis'') is the star's Bayer designation, established in 1603 as part of the ''Uranometria'', a star catalogue produced by German celestial cartographer Johann Bayer. It bore the traditional name ''Alsafi'', derived from the Arabic ''Athāfi'', itself erroneously transcribed from the Arabic plural ''Athāfiyy'', by which the nomads designated the tripods of their open-air kitchens. It was the name of an association of this st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma Draconis
Sigma Draconis is a single star in the northern constellation of Draco. It has the proper name Alsafi , while Sigma Draconis, which is latinised from σ Draconis and abbreviated Sig Dra or σ Dra, is the Bayer designation. It has an apparent visual magnitude of 4.7, which is bright enough to be faintly visible to the naked eye. Based on parallax measurements, this star is located at a distance of 18.8 light years from the Sun. It is receding from the Sun with a radial velocity of 26.8 km/s. Name ''σ Draconis'' ( Latinised to ''Sigma Draconis'') is the star's Bayer designation, established in 1603 as part of the ''Uranometria'', a star catalogue produced by German celestial cartographer Johann Bayer. It bore the traditional name ''Alsafi'', derived from the Arabic ''Athāfi'', itself erroneously transcribed from the Arabic plural ''Athāfiyy'', by which the nomads designated the tripods of their open-air kitchens. It was the name of an association of this st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAU Working Group On Star Names
The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education, Outreach and Heritage. The IAU states that it is keen to make a distinction between the terms ''name'' and ''designation''. To the IAU, ''name'' refers to the (usually colloquial) term used for a star in everyday conversation, while ''designation'' is solely alphanumerical, and used almost exclusively in official catalogues and for professional astronomy. (The WGSN notes that transliterated Bayer designations (e.g., Tau Ceti) are considered a special historical case and are treated as designations.) Terms of reference The terms of reference for the WGSN for the period 2016–2018 were approved by the IAU Executive Committee at its meeting on 6 May 2016. In summary, these are to: * establish IAU guidelines for the proposal and a ... [...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 coo ... [...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 coo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium. During this stage of the star's lifetime, it is located on the main sequence at a position determined primarily by its mass but also based on its chemical composition and age. The cores of main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Star Names
Chinese star names (Chinese: , ''xīng míng'') are named according to ancient Chinese astronomy and astrology. The sky is divided into star mansions (, ''xīng xiù'', also translated as "lodges") and asterisms (, ''xīng guān''). The system of 283 asterisms under Three Enclosures and Twenty-eight Mansions was established by Chen Zhuo of the Three Kingdoms period, who synthesized ancient constellations and the asterisms created by early astronomers Shi Shen, Gan De and Wuxian. Since the Han and Jin Dynasties, stars have been given reference numbers within their asterisms in a system similar to the Bayer or Flamsteed designations, so that individual stars can be identified. For example, Deneb (α Cyg) is referred to as (''Tiān Jīn Sì'', the Fourth Star of Celestial Ford). In the Qing Dynasty, Chinese knowledge of the sky was improved by the arrival of European star charts. ''Yixiang Kaocheng'', compiled in mid-18th century by then deputy Minister of Rites Ignaz Kögler, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pi Draconis
Pi Draconis, Latinized from π Draconis, is a solitary star in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of 4.59. Based upon an annual parallax shift of 14.25 mas as measured from Earth, it is located around 229 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of due to interstellar dust. With an age of 350 million years, this is an A-type star of stellar classification A2 IIIs, where the luminosity class of III typically indicates an evolved giant star and the 's' means the spectrum displays sharp absorption lines. It is a candidate Am star, meaning there are some chemical peculiarities. The measured angular size is . At the estimated distance of Pi Draconis, this yields a physical size of about 3.2 times the radius of the Sun. It has about 2.70 times the mass of the Sun and is radiating 60 times the solar luminosity The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
64 Draconis
64 Draconis is a single star in the northern circumpolar constellation of Draco, located 452 light years away. It has the Bayer designation of e Draconis; ''64 Draconis'' is the Flamsteed designation. The object is visible to the naked eye as a dim, red-hued star with an apparent visual magnitude of 5.27. It is moving closer to the Earth with a heliocentric radial velocity of −36 km/s, and it is predicted to come as close as in around 4.3 million years. This is an evolved red giant star with a stellar classification of M1 III, currently on the asymptotic giant branch. It has expanded to about 65 times the Sun's radius and is radiating 926 times the Sun's luminosity from its photosphere at an effective temperature of . 64 Draconis forms a faint naked-eye pair with 65 Draconis away. The latter is a suspected variable with a brightness range in the Hipparcos photometric filter of 5.29 to 5.33. In Chinese Chinese can refer to: * Somethi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rho Draconis
Rho Draconis (ρ Draconis) is a solitary star in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.52. Based upon an annual parallax shift of 7.61 mas as measured from Earth, it is located around 429 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.027 due to interstellar dust. With a stellar classification of K3 III, Rho Draconis is a normal giant star that is past the first dredge-up phase of its post- main sequence evolution. It has the peculiar spectrum of a CN star, showing abnormal line strengths for cyanogen and calcium. The star has expanded to around 28 times the Sun's radius and it is radiating 402 times the solar luminosity 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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Draconis
Epsilon Draconis, Latinized from ε Draconis, is a fourth-magnitude star in the constellation Draco. This star along with Delta Draconis (Altais), Pi Draconis and Rho Draconis forms an asterism known as Al Tāis, meaning "the Goat". In Chinese astronomy, (), meaning the Celestial Kitchen, refers to an asterism consisting of Epsilon Draconis, Delta Draconis, Sigma Draconis, Rho Draconis, 64 Draconis and Pi Draconis. Consequently, the Chinese name for Epsilon Draconis itself is (, en, the Third Star of the Celestial Kitchen.) Most authors do not use a traditional name for this star, using instead the Bayer designation; but Bečvář (1951) listed it as Tyl . Visibility With a declination in excess of 70 degrees north, Epsilon Draconis is principally visible in the northern hemisphere, with southern locations north of 20° South able to see it just above the horizon. The star is circumpolar throughout all of Europe, China, most of India and as far south as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Draconis
Delta Draconis (δ Draconis, abbreviated Delta Dra, δ Dra), formally named Altais , is a yellow star in the constellation of Draco. It has an apparent visual magnitude of 3.0, making it easily visible to the naked eye. Based on parallax measurements obtained during the Hipparcos mission, it is approximately from the Sun. Nomenclature ''δ Draconis'' ( Latinised to ''Delta Draconis'') is the star's Bayer designation. It bore the traditional names ''Aldib'', ''Altais'' (the goat) and ''Nodus Secundus''. The title ''Altais'' was derived from Arabic ''Al Tāis'' "the Goat", the association of this star, along with Pi Draconis, Rho Draconis and Epsilon Draconis (Tyl). According to a 1971 NASA catalog of stars, ''Al Tāis'' or ''Tais'' were the title for three stars : Delta Draconis as ''Altais'', Pi Draconis as ''Tais I'' and Rho Draconis as ''Tais II'' (exclude Epsilon Draconis). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
