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γ Cen
Gamma Centauri, Latinized from γ Centauri, is a binary star system in the southern constellation of Centaurus. It has the proper name Muhlifain, not to be confused with Muliphein, which is γ Canis Majoris; both names derive from the same Arabic root. The system is visible to the naked eye as a single point of light with a combined apparent visual magnitude of +2.17; individually they are third-magnitude stars. This system is located at a distance of about from the Sun based on parallax. In 2000, the pair had an angular separation of 1.217 arcseconds with a position angle of 351.9°. Their positions have been observed since 1897, which is long enough to estimate an orbital period of 84.5 years and a semimajor axis of 0.93 arcsecond. At the distance of this system, this is equivalent to a physical separation of about . The combined stellar classification of the pair is A1IV+; when they are separated out they have individual classes of A1IV and A0IV, suggesting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centaurus
Centaurus is a bright constellation in the southern sky. One of the 88 modern constellations by area, largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. In Greek mythology, Centaurus represents a centaur; a creature that is half human, half horse (another constellation named after a centaur is one from the zodiac: Sagittarius (constellation), Sagittarius). Notable stars include Alpha Centauri, the nearest star system to the Solar System, its neighbour in the sky Beta Centauri, and V766 Centauri, one of the largest stars yet discovered. The constellation also contains Omega Centauri, the brightest globular cluster as visible from Earth and the largest identified in the Milky Way, possibly a remnant of a dwarf galaxy. Notable features Stars Centaurus contains several very bright stars. Its alpha and beta stars are used as "pointer stars" to help observers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comoving And Proper Distances
In standard cosmology, comoving distance and proper distance are two closely related distance measures used by cosmologists to define distances between objects. ''Proper distance'' roughly corresponds to where a distant object would be at a specific moment of cosmological time, which can change over time due to the expansion of the universe. ''Comoving distance'' factors out the expansion of the universe, giving a distance that does not change in time due to the expansion of space (though this may change due to other, local factors, such as the motion of a galaxy within a cluster). Comoving distance and proper distance are defined to be equal at the present time. At other times, the Universe's expansion results in the proper distance changing, while the comoving distance remains constant. Comoving coordinates Although general relativity allows one to formulate the laws of physics using arbitrary coordinates, some coordinate choices are more natural or easier to work with. Com ... [...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] |
σ Centauri
Sigma Centauri, Latinized from σ Centauri, is the Bayer designation for a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of 3.91. A visual companion at an angular separation of along a position angle of was detected in 2010 using interferometry, but its association with Sigma Centauri remains undetermined as of 2013. The distance to Sigma Centauri, based upon an annual parallax shift of 7.92 mas, is around 412 light years. This is a B-type main sequence star with a stellar classification of B3 V. It is a helium-rich star, the most massive type of chemically peculiar star. Sigma Centauri has around 6.8 times the mass of the Sun and 4.5 times the Sun's radius. It has a relatively high rate of spin with a projected rotational velocity of 169 km/s, and is around 25 million years old. The star radiates 1,101 times the solar luminosity from its outer atmosphere at an effective te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D Centauri
D Centauri is a double star in the southern constellation of Centaurus. The system is faintly visible to the naked eye as a point of light with a combined apparent magnitude of +5.31; the two components are of magnitude 5.78 and 6.98, respectively. It is located at a distance of approximately 610 light years from the Sun based on parallax, and is drifting further away with a radial velocity of ~10 km/s. The dual nature of this star was announced by C. Rumker in 1837. As of 2015, the pair had an angular separation of along a position angle of 242°. This orange-hued double has a combined stellar classification of K3III, matching an aging giant star that has exhausted the supply of hydrogen at its core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central .... In 1984, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
τ Centauri
Tau Centauri, Latinized from τ Centauri, is a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.86. The distance to this star, based upon an annual parallax shift of 24.85 mas, is 131 light years. There is a 98% chance that it is a co-moving companion of Gamma Centauri; the two stars have an estimated separation of . This is an A-type star with stellar classifications of A0 V or A1 IVnn, indicating it may be a main sequence star or a more evolved subgiant star. It is around 132 million years old and is spinning rapidly with a projected rotational velocity of 296.8 km/s. This is giving the star an oblate shape, with an estimated equatorial girth that is 30% larger than the polar radius. The star has an estimated 2.3 times the mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi1 Centauri
Xi1 Centauri, Latinized from ξ1 Centauri, is a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +4.83. With an annual parallax shift of 14.79 mas, it is located around 221 light years from the Sun. At that distance, the apparent visual magnitude of the star is diminished by an interstellar extinction factor of 0.10 due to intervening dust. Just 17 arc minutes to the east of Xi1 Centauri lies the galaxy NGC 4945. This is an A-type main sequence star with a stellar classification of A0 V. It is about 125 million years old with a relatively high rate of spin, having a projected rotational velocity of 185 km/s. The star has an estimated 2.4 times the mass of the Sun and about 2.7 times the Sun's radius. It is radiating 43 times the solar luminosity from its outer atmosphere at an effective temperature The effective temperature of a body such as a star or planet is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 117440
HD 117440, also known by its Bayer designation d Centauri, is a binary star system in the southern constellation of Centaurus. It is visible to the naked eye with a combined apparent visual magnitude of 3.90. The distance to this system is approximately 900 light years based on parallax measurements. It is drifting closer to the Sun with a radial velocity of −2 km/s. A companion star was first reported by T. J. J. See in 1897 at an angular separation of from the primary. Orbital elements for the pair were published by W. S. Finsen in 1962 then updated in 1964, yielding an orbital period of 83.1 years with a semimajor axis of and an eccentricity of 0.52. Both components are evolved G-type giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2 Centauri
2 Centauri is a single star in the Southern celestial hemisphere, southern constellation of Centaurus, located approximately 183 light-years from Earth. It has the Bayer designation g Centauri; ''2 Centauri'' is the Flamsteed designation. This object is visible to the naked eye as faint, red-hued star with an apparent visual magnitude of 4.19. It is moving away from the Earth with a heliocentric radial velocity of +41 km/s. The star is a member of the HD 1614 supercluster. This is an stellar evolution, evolved red giant star with a stellar classification of M5 III. It is classified as a semiregular variable star, semiregular variable star and its brightness varies from magnitude +4.16 to +4.26 with a period of 12.57 days. The star has around 70 times the Sun's radius and is radiating 72 times the Sun's luminosity from its enlarged photosphere at an effective temperature of . References {{DEFAULTSORT:2 Centauri M-type giants Asymptotic-giant-branch stars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
θ Centauri
Theta Centauri or θ Centauri, officially named Menkent (), is a single star in the southern constellation of Centaurus, the centaur. With an apparent visual magnitude of +2.06, it is the fourth-brightest member of the constellation. Based on parallax measurements obtained during the Hipparcos mission, it is about distant from the Sun. It has a relatively high proper motion, traversing the celestial sphere at the rate of . Nomenclature ''θ Centauri'', Latinised to ''Theta Centauri'', is the star's Bayer designation. It bore the traditional name of ''Menkent'' derived from the Arabic word مَنْكِب (mankib)for "shoulder" (of the Centaur), apparently blended with a shortened form of "kentaurus" (centaur). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name ''Menkent'' for this star on 21 August 2016 and it is now so included in the List of IAU- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
η Centauri
Eta Centauri, Latinized from η Centauri, is a star in the southern constellation of Centaurus. It has an apparent visual magnitude of +2.35 and is located at a distance of around . The stellar classification of this star is B1.5 Vne, indicating that it is a B-type main sequence star. The 'n' suffix means that the absorption lines are broadened from rapid rotation and the 'e' that it shows emission lines in its spectrum. It has a projected rotational velocity of 330 km s−1 and completes a full rotation in less than a day. As a Be star, it has variable emissions in its hydrogen spectral lines. This emission can be modelled by a decretion disk of gas that has been ejected from the star by its rapid rotation and now follows a near-Keplerian orbit around the central body. Its brightness is also slightly variable, and it is classified as a Gamma Cassiopeiae variable star with multiple periods of variability. The International Variable Star Index lists Eta Centaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ζ Centauri
Zeta Centauri, Latinized from ζ Centauri, is a binary star system in the southern constellation of Centaurus. It has the proper name Alnair , from the Arabic ''Nayyir Baṭan Qanṭūris'' (نير بطن قنطورس), meaning "The Bright (Star) of the Body of the Centaur". With a combined apparent visual magnitude of +2.55, it is one of the brighter members of the constellation. This system is close enough to the Earth that its distance can be measured directly using the parallax technique. This yields a value of roughly , with a 1.6% margin of error. It is drifting further away with a radial velocity of +6.5 km/s. In Chinese, (), meaning ''Arsenal'', refers to an asterism consisting of ζ Centauri, η Centauri, θ Centauri, 2 Centauri, HD 117440, ξ1 Centauri, γ Centauri, τ Centauri, D Centauri and σ Centauri. Consequently, the Chinese name for ζ Centauri itself is (, en, the First Star of Arsenal.) ζ Cen is a double-lined spectroscopic binary system, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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