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Omicron Sagittarii
ο Sagittarii, Latinized as Omicron Sagittarii, is a single star in the constellation Sagittarius. It is yellow in hue and visible to the naked eye with an apparent visual magnitude of +3.77. The distance to this star is approximately 142 light years based on parallax. It is drifting further away from the Sun with a radial velocity of +26 km/s, having come to within around a million years ago. This object is position 0.86 degrees north of the ecliptic, so ο Sagittarii can be occulted by the Moon and very rarely by planets. The last occultation by a planet took place on 24 December 1937, when it was occulted by Mercury. It was almost eclipsed by the sun, which occupies a mean, rounded, half of one degree of the sky, on 5 January. Thus the star can be viewed the whole night, crossing the sky, in early July. This is an aging giant star with a stellar classification of G9IIIb. It is classified as a red clump giant, suggesting it is on the horizontal branch u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittarius (constellation)
Sagittarius is one of the constellations of the zodiac and is located in the Southern celestial hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy and remains one of the 88 modern constellations. Its old astronomical symbol is (♐︎). Its name is Latin for "archer". Sagittarius is commonly represented as a centaur pulling back a bow. It lies between Scorpius and Ophiuchus to the west and Capricornus and Microscopium to the east. The center of the Milky Way lies in the westernmost part of Sagittarius (see Sagittarius A). Visualizations As seen from the northern hemisphere, the constellation's brighter stars form an easily recognizable asterism known as "the Teapot". The stars δ Sgr (Kaus Media), ε Sgr (Kaus Australis), ζ Sgr (Ascella), and φ Sgr form the body of the pot; λ Sgr (Kaus Borealis) is the point of the lid; γ2 Sgr (Alnasl) is the tip of the spout; and σ Sgr (Nunki) and τ Sgr the handle. These same sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of the Sun. This equates to about two nonillion (short scale), two quintillion (long scale) kilograms or 2000 quettagrams: The solar mass is about times the mass of Earth (), or times the mass of Jupiter (). History of measurement The value of the gravitational constant was first derived from measurements that were made by Henry Cavendish in 1798 with a torsion balance. The value he obtained differs by only 1% from the modern value, but was not as precise. The diurnal parallax of the Sun was accurately measured during the transits of Venus in 1761 and 1769, yielding a value of (9 arcseconds, compared to the present value of ). From the value of the diurnal parallax, one can determine the distance to the Sun from the geometry o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...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] |
Upsilon Sagittarii
Upsilon Sagittarii (Upsilon Sgr, υ Sagittarii, υ Sgr) is a spectroscopic binary star system in the constellation Sagittarius (constellation), Sagittarius. Upsilon Sagittarii is the prototypical hydrogen-deficient binary (HdB), and one of only four such systems known. The unusual stellar spectrum, spectrum of hydrogen-deficient binaries has made stellar classification of Upsilon Sagittarii difficult. System υ Sgr is a binary star, binary system with an orbital period of 137.939 days and is approximately 1,800 light years from Earth. The primary star dominates the visible radiation and spectrum, but the secondary is hotter and more massive. Some sources consider the "invisible" component to be the primary on the basis of its mass. There is also a disc of material being stripped from the primary and transferring material to the secondary, but no eclipses The system is classified as a single-lined spectroscopic binary, but high excitation lines from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rho1 Sagittarii
Rho1 Sagittarii, Latinized from ρ1 Sagittarii, is a single, variable star in the southern constellation of Sagittarius. It has a white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around 3.93. The distance to this star is approximately 127 light years based on parallax, and it is drifting further away with a radial velocity of +1.2 km/s. It is positioned near the ecliptic and so it can be occulted by the Moon. This object has a stellar classification of A9IV, matching a subgiant star that is evolving away from the main sequence. It is a low amplitude Delta Scuti variable, ranging from 3.94 to 3.90 magnitude with a period of 0.05 days. The star is 893 million years old and is spinning with a projected rotational velocity of 68 km/s. It has 1.9 times the mass of the Sun and 3.3 times the Sun's radius. The star is radiating 31 times the luminosity of the Sun from its photosphere at an effective temperature Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
43 Sagittarii
43 Sagittarii is a single star in the southern constellation of Sagittarius. It has the Bayer designation d Sagittarii, while ''43 Sagittarii'' is the Flamsteed designation. This object is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.88. From parallax measurements, it is estimated to lie around 470 light years away from the Sun. The star is drifting further from the Earth with a heliocentric radial velocity of +15.2 km/s. It is located near the ecliptic and thus is subject to lunar occultations. This is an aging giant/bright giant star with a stellar classification of G8II-III, and is most likely (97% chance) on the horizontal branch. It is around 350 million years old with 3.3 times the mass of the Sun. Having exhausted the supply of hydrogen at its core, the star has expanded to 24 times the Sun's radius and is now generating energy through core helium fusion. It is radiating 277 times the luminosity of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pi Sagittarii
Pi Sagittarii (π Sagittarii, abbreviated Pi Sgr, π Sgr) is a triple star system in the zodiac constellation of Sagittarius. It has an apparent visual magnitude of +2.89, bright enough to be readily seen with the naked eye. Based upon parallax measurements, it is roughly from the Sun. The three components are designated Pi Sagittarii A (officially named Albaldah , from the traditional name of the entire system), B and C. Nomenclature ''π Sagittarii'' ( Latinised to ''Pi Sagittarii'') is the system's Bayer designation. The designations of the three constituents as ''Pi Sagittarii A'', ''B'' and ''C'', derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). The system bore the traditional name ''Albaldah'', which comes from the Arabic بلدة ''bálda'' 'the town'. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi2 Sagittarii
Xi2 Sagittarii, Latinized from ξ2 Sagittarii, is a star in the zodiac constellation of Sagittarius. Data collected during the Hipparcos mission suggests it is an astrometric binary, although nothing is known about the companion. It is visible to the naked eye with a combined apparent visual magnitude of +3.51. Based upon an annual parallax shift of 8.93 mas as seen from Earth, this system is located around 370 light years from the Sun. The spectrum of Xi2 Sagittarii yields a mixed stellar classification of G8/K0 II/III, showing traits of a G- or K-type giant or bright giant star. It has an estimated 3.36 times the mass of the Sun and about 14 times the Sun's radius. At an age of around 380 million years, it is radiating 676 times the Sun's luminosity from its photosphere at an 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 electromag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipper (Chinese Constellation)
The Dipper mansion (斗宿, pinyin: Dǒu Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise. In Taoism, it is known as the "Six Stars of the Southern Dipper" (南斗六星, Nándǒu liù xīng), in contrast to the Big Dipper The Big Dipper ( US, Canada) or the Plough ( UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" ... north to this mansion. Asterisms Stars * ζ Sgr * τ Sgr * σ Sgr * φ Sgr * λ Sgr * μ Sgr {{DEFAULTSORT:Dipper (Chinese Constellation) Chinese constellations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Astronomy
Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 ''xiù'') system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE). Detailed records of astronomical observations began during the Warring States period (fourth century BCE) and flourished from the Han period onward. Chinese astronomy was equatorial, centered on close observation of circumpolar stars, and was based on different principles from those in traditional Western astronomy, where heliacal risings and settings of zodiac constellations formed the basic ecliptic framework. Joseph Needham has described the ancient Chinese as the most persistent and accurate obser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Position Angle
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the direction of the right ascension. In the standard (non-flipped) images, this is a counterclockwise measure relative to the axis into the direction of positive declination. In the case of observed visual binary stars, it is defined as the angular offset of the secondary star from the primary relative to the north celestial pole. As the example illustrates, if one were observing a hypothetical binary star with a PA of 135°, that means an imaginary line in the eyepiece drawn from the north celestial pole to the primary (P) would be offset from the secondary (S) such that the angle would be 135°. When graphing visual binaries, the NCP is, as in the illustration, normally drawn from the center point (origin) that is the Primary downward&nd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
