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Xi Piscium
Xi Piscium (ξ Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. In 1690, the astronomer Johannes Hevelius in his ''Firmamentum Sobiescianum'' regarded the constellation Pisces as being composed of four subdivisions. Xi Piscium was considered to be part of the ''Linum Austrinum'', the South Cord. The star is visible to the naked eye, having an apparent visual magnitude of 4.60. Based upon an annual parallax shift of 11.67 mas as seen from Earth, it is located about 280 light years from the Sun. It is moving away from the Sun, having a radial velocity of +26 km/s. This is a single-lined spectroscopic binary system with an orbital period of 4.6 years and an eccentricity of around 0.18. The spectroscopic binary nature of this star was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory. The visible component is an evolved K-type giant star with a stellar classificati ... [...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] |
Stellar Evolution
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star. Nuclear fusion powers a star for most of its existence. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nu Piscium
Nu Piscium (ν Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. Prior to the formation of the modern constellation boundaries in 1930, it was designated 51 Ceti in the Cetus constellation. Nu Piscium is visible to the naked eye, having a combined apparent visual magnitude of 4.44. Based upon an annual parallax shift of 8.98 mas as seen from Earth, it is located about 363 light years from the Sun. The primary, component A, is an evolved, K-type giant star with a stellar classification of K3 IIIb. It is a weak barium star, indicating that the atmosphere was previously enriched by accretion of s-process elements from what is now a white dwarf companion. The giant has 1.66 times the mass of the Sun and has expanded to about 34 times the Sun's radius. It is about 3.4 billion years old and is radiating 380 times the Sun's luminosity from its photosphere at an effective temperature of 4,154 K. Naming In Chinese, () ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mu Piscium
Mu Piscium (μ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.84. Based upon an annual parallax shift of 10.73 mas as seen from Earth, it is located about 304 light years from the Sun. Given this distance, it has a relatively high proper motion, advancing 296 mas per year across the sky. This is an evolved K-type giant star with a stellar classification of K4 III. It has an estimated 1.25 times the mass of the Sun and, at the age of 5.6 billion years, has expanded to about 37 times the Sun's radius. From this enlarged photosphere, it is radiating 186 times the Sun's luminosity at an effective temperature of 4,126 K. It has a magnitude 12.02 visual companion at an angular separation of 209.30 arc seconds along a position angle of 298°, as of 2012. Naming In Chinese, (), meaning '' Outer Fence'', refers to an asterism consisting of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Piscium
Zeta Piscium (ζ Piscium, abbreviated Zet Psc, ζ Psc) is a quintuple star system in the zodiac constellation of Pisces. Based upon parallax measurements obtained during the Hipparcos mission, it is located roughly distant from the Sun. The system consists of a binary star (Zeta Piscium A) and a triple star system (BC), the latter consisting of a spectroscopic binary (B) and a single star (C). A's two components are themselves designated Zeta Piscium Aa (officially named Revati ) and Ab; B's two components as Ba and Bb. As the star system is 0.21° south of the ecliptic, it can be eclipsed ( occulted) by the moon, when close to or at one of its two nodes of its orbit; and is eclipsed by the sun from about 8-10 April. Nomenclature ''ζ Piscium'' ( Latinised to ''Zeta Piscium'') is the system's Bayer designation. The designations of the three constituents as ''Zeta Piscium A'', ''B'' and ''C'', and those of ''A's'' and ''B's'' components - ''Zeta Piscium Aa'', ''Ab'', ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Piscium
Epsilon Piscium (Epsilon Psc, ε Piscium, ε Psc) is the Bayer designation for a star approximately away from the Earth, in the constellation Pisces. It is a yellow-orange star of the G9 III or K0 III spectral type, meaning it has a surface temperature around 5,000 kelvins. This is a normal giant star, slightly cooler in surface temperature, yet brighter and larger than the Sun. It is a suspected occultation double, with both stars having the same magnitude, separated by 0.25 arcsecond. Naming In Chinese, (), meaning '' Outer Fence'', refers to an asterism consisting of ε Piscium, δ Piscium, ζ Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, the Chinese name for ε Piscium itself is (, en, the Second Star of Outer Fence.) In Japanese, 悠翔星 (Haruto-boshi), meaning "Soaring Forever Star," refers to the Japanese description of ε Piscium. Planetary system In 2021, a gas giant planetary candidate was de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Piscium
Delta Piscium (δ Piscium) is a solitary, orange-hued star in the zodiac constellation of Pisces. It has an apparent visual magnitude of +4.4, so it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 10.5 mas, it is around from the Sun. The visual magnitude of the star is diminished by an interstellar absorption factor of 0.08 due to interstellar dust. This is an evolved K-type giant star with a stellar classification of K4 IIIb. It has around 1.65 times the mass of the Sun and, at the age of three billion years, has expanded to 44 times the Sun's radius. The star is radiating 447 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,963 K. Because Delta Piscium is positioned near the ecliptic, so it is subject to lunar occultations. It has a magnitude 13.99 visual companion at an angular separation of 135.0 arc seconds on a position angle of 12°, as of 2011. Naming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Legs (Chinese Constellation)
The Legs mansion (奎宿, pinyin: Kuí Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger The white tiger or bleached tiger is a leucistic pigmentation variant of the Mainland tiger. It is reported in the wild from time to time in the Indian states of Madhya Pradesh, Assam, West Bengal, Bihar, Odisha, in the Sunderbans region and .... Cultural significance In East Asian cultures, the Legs mansion (Kuí Xiù) represents wisdom, scholarship and literature. A notable example is a structure known as "Kuiwen Pavilion" (奎文閣) in the many Confucius temples in China and other East Asian countries. Asterisms See also * Kui Xing {{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] |
Helium Fusion
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. Triple-alpha process in stars Helium accumulates in the cores of stars as a result of the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle. Nuclear fusion reaction of two helium-4 nuclei produces beryllium-8, which is highly unstable, and decays back into smaller nuclei with a half-life of , unless within that time a third alpha particle fuses with the beryllium-8 nucleus to produce an excited resonance state of carbon-12, called the Hoyle state, which nearly always decays back into three alpha particles, but once in about 2421.3 times releases energy and changes into the stable base form of carbon-12. When a star runs out of hydrogen to fuse in its core, it begins to contract and heat up. If the central temperature rises to 108 K, six times hotter than the Sun's core, alpha particles can fuse fast enough to get pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Clump
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color (made from magenta and yellow) in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. Red pigment made from ochre was one of the first colors used in prehistoric art. The Ancient Egyptians and Mayans colored their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories. It was also an important color in China, where it was used to color early pottery and later the gates and walls of palaces. In the Renaissance, the brilliant red costumes for the nobility and wealthy were dyed with kermes and cochineal. The 19th century brought the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
