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Epsilon Capricorni
Epsilon Capricorni, Latinized from ε Capricorni, is a possible binary star system in the constellation Capricornus. It has the traditional star name Kastra, meaning "fort" or "military camp" in Latin. Based upon an annual parallax shift of 3.09 mas as seen from the Earth, the star is located about 1,060 light years from the Sun. It can be seen with the naked eye, having a combined apparent visual magnitude of 4.62. In Chinese, (), meaning '' Line of Ramparts'', refers to an asterism consisting of ε Capricorni, κ Capricorni, γ Capricorni, δ Capricorni, ι Aquarii, σ Aquarii, λ Aquarii, φ Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium. Consequently, the Chinese name for ε Capricorni itself is (, en, the Second Star of Line of Ramparts.) The binary system has an orbital period of 129 days. The primary, component Aa, is a Be star that is surrounded by ionized gas that is producing the emission lines in the spectrum. This circ ... [...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] |
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects show a larger parallax than farther objects when observed from different positions, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term ''parallax'' is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit. These distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Parallax also affects optical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
27 Piscium
27 Piscium is a binary star system in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.88. Based upon an annual parallax shift of , it is located about 234 light years away. The system is positioned near the ecliptic and so is subject to occultation by the Moon. This star was found to be a double by American astronomer S. W. Burnham. By 2002, sufficient position data had been gathered that orbital motion could be demonstrated, and preliminary elements were determined. The system has an orbital period of 695 years and an eccentricity of 0.766. However, the orbital elements do not fully explain the radial velocity variations, which may indicate there is a brown dwarf companion. This candidate object would have a mass of at least and is orbiting with a semimajor axis of around . At the age of around 710 million years, the primary, component A, is a first ascent giant star on the red giant branch with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phi Aquarii
Phi Aquarii, Latinized from φ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of +4.223. Parallax measurements indicate its distance from Earth is roughly , and it is drifting further away with a radial velocity of +2.5 km/s. It is 1.05 degrees south of the ecliptic so it is subject to lunar occultations. This is a spectroscopic binary star system with an estimated period of 2,500 days. The primary component is a red giant star with a stellar classification of M1.5 III. The outer envelope of this evolved star has expanded to 35 times the size of the Sun. The star has the same mass as the Sun. It is radiating 208 times the luminosity of the Sun at an effective temperature of 3,715 K, giving it the reddish hue of an M-type star In astronomy, stellar classification is the classification of stars based on their spectral ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Aquarii
Lambda Aquarii, informally known as Hydor (), is a variable star in the equatorial constellation of Aquarius. The name is Latinized from the Bayer designation λ Aquarii. The apparent visual magnitude of this star ranges from 3.57 down to 3.80, which is bright enough to be visible with the naked eye. It lies just 0.39 degrees south of the ecliptic and so is subject to lunar occultations. The star is eclipsed by the sun from about 1-4 March; thus the star can be viewed the whole night, crossing the sky, in early September, in the current epoch. Lambda Aquarii is located at a distance of approximately from the Sun based on parallax, but is drifting closer with a radial velocity of −10.5 km/s. The stellar classification of Lambda Aquarii is , indicating this is an aging red giant star with an underabundance of iron showing in its spectrum. This star is on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma Aquarii
Sigma Aquarii, Latinized from σ Aquarii, is a double star in the equatorial constellation of Aquarius, positioned about 1.3° to the south of the ecliptic. Due to its proximity to the ecliptic, this star is subject to occultation by the Moon. It has a white hue and is visible to the naked eye with an apparent visual magnitude of 4.81. Based upon parallax measurements, the distance to this star is approximately . It is drifting further away with a radial velocity of +11 km/s. The stellar classification of Sigma Aquarii is A0 IVs, indicating that it is a subgiant star. The ''s'' qualifier means that its absorption lines are sharp (narrow) in comparison with standard stars, caused by a relatively slow rotation. It has been categorized as a hot Am star, meaning that it is a chemically peculiar, although this is now considered doubtful. The spectrum displays at least double the normal abundances of elements like magnesium, aluminum and silicon, while helium and sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iota Aquarii
Iota Aquarii, Latinised from ι Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279. Based upon parallax measurements made during the ''Hipparcos'' mission, the distance to this star is around . The system is drifting closer to the Sun with a radial velocity of −10 km/s. The binary nature of this system was reported in 2009 following a radial velocity survey using the HARPS instrument. A 2010 infrared search for companions around this star was unsuccessful. The presence of a stellar companion was confirmed through direct spectral detection in 2016. The companion shows a significant velocity variation over a 77-day interval, suggesting a short orbital period. The spectrum of the primary, component A, fits a stellar classification of B8 V, showing that this is a B-type main-sequence star. It is roughly 124 million years old and is spinnin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Capricorni
Delta Capricorni, or δ Capricorni, is a binary star located 38,7 light-years from the Sun in the constellation of Capricornus (the Sea Goat). The system consists of an eclipsing binary, Delta Capricorni A, and two visual companions that are over 10 magnitudes fainter, labeled B and C. Delta Capricorni A's two components are designated Delta Capricorni Aa (formally named Deneb Algedi , the traditional name of the system) and Ab. The primary star, Aa, is a white giant and the combined light of Aa and Ab makes it the brightest star in the constellation. Delta Capricorni is 2.6 degrees south of the ecliptic and can be occulted by the Moon, and (rarely) by planets. Nomenclature ''δ Capricorni'' ( Latinised to ''Delta Capricorni'') is the system's Bayer designation. The designations of the three constituents as ''Delta Capricorni A'', ''B'' and ''C'', and those of ''A's'' components – ''Delta Capricorni Aa'' and ''Ab'' – derive from the convention used by the Washin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Capricorni
Gamma Capricorni or γ Capricorni, formally named Nashira (), is a giant star in the constellation of Capricornus. Based on parallax measurements obtained during the Hipparcos mission, it is located at a distance of approximately 157 light-years from the Sun. The star is drifting closer with a radial velocity of −31 km/s. It is 2.56 degrees south of the ecliptic, so it can be occulted by the Moon, and (rarely) by planets. Nomenclature ''γ Capricorni'' ( Latinised to ''Gamma Capricorni'') is the star's Bayer designation. It bore the traditional name ''Nashira'', derived from the Arabic سعد ناشرة ''sa'd nashirah'' "the lucky one" or "bearer of good news". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name ''Nashira'' for this star on 21 August 2016 and it is now so included in the List of IAU-approved Star Names. In Chinese, (), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kappa Capricorni
Kappa Capricorni (κ Cap, κ Capricorni) is a solitary star in the constellation Capricornus. It is visible to the naked eye with an apparent visual magnitude of +4.73. Based upon an annual parallax shift of 11.09 mas as seen from the Earth, the star is located about 294 light years from the Sun. This is a yellow-hued, evolved, G-type giant star with a stellar classification of G8 III. There is a 91% probability that it is currently on the horizontal branch, rather than the red giant branch. As such, it is a red clump giant with an estimated 2.43 times the mass of the Sun and has expanded to 13.28 times the radius of the Sun. The star is about 1.2 billion years old and has a projected rotational velocity that is too small to be measured. It radiates 107 times the solar 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 amou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encampment (Chinese Constellation)
The Encampment mansion () is one of the 28 mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise The Black Tortoise () is one of the Four Symbols of the Chinese constellations. Despite its English name, it is usually depicted as a tortoise entwined together with a snake. The name used in East Asian languages does not mention either anima .... Asterisms References {{DEFAULTSORT:Encampment (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] |
