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Xi1 Ceti
Xi1 Ceti , Latinized from ξ1 Ceti, is a binary star system located in the equatorial constellation of Cetus. It is visible to the naked eye with a combined apparent visual magnitude of +4.36. The distance to this system is approximately 340 light years based on parallax measurements, and it is drifting closer to the Sun with a radial velocity of −4 km/s. The proximity of the star to the ecliptic means it is subject to lunar occultations. The spectroscopic binary nature of Xi1 Ceti was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory. The pair have a circular orbit with a period of 4.5 years and a separation of . It is a suspected eclipsing binary with an amplitude of 0.03 in magnitude, which would suggest the orbital plane has a high inclination. The primary, designated component A, is a mild barium giant star with a stellar classification of . Morgan and Keenan in 1973 had classified it as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetus
Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water-related constellations: Aquarius (constellation), Aquarius, Pisces (constellation), Pisces and Eridanus (constellation), Eridanus. Features Ecliptic Cetus is not among the 12 true zodiac constellations in the Epoch (astronomy), J2000 epoch, nor classical 12-part zodiac. The ecliptic passes less than 0.25° from one of its corners. Thus the moon and planets will enter Cetus (occulting any stars as a foreground object) in 50% of their successive orbits briefly and the southern part of the sun appears in Cetus for about one day each year. Many asteroids in belts have longer phases occulting the north-western part of Cetus, those with a slightly greater inclination to the ecliptic than the moon and planets. Astronomy on Mars#Celestial pole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barium Star
Barium stars are spectral class G to K stars whose spectra indicate an overabundance of s-process elements by the presence of singly ionized barium, Ba II, at λ 455.4 nm. Barium stars also show enhanced spectral features of carbon, the bands of the molecules CH, CN and C2. The class was originally recognized and defined by William P. Bidelman and Philip Keenan. Initially, after their discovery, they were thought to be red giants, but the same chemical signature has been observed in main-sequence stars as well. Observational studies of their radial velocity suggested that all barium stars are binary stars. Observations in the ultraviolet using International Ultraviolet Explorer detected white dwarfs in some barium star systems. Barium stars are believed to be the result of mass transfer in a binary star system. The mass transfer occurred when the now-observed giant star was on the main sequence. Its companion, the donor star, was a carbon star on the asymptotic gian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi2 Ceti
Xi2 Ceti, Latinized from ξ2 Ceti, is a star located in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of +4.3. This star is located at a distance of approximately 197 light years from the Sun based on parallax, and is drifting further away with a radial velocity of 12 km/s. It made its closest approach some 2.7 million years ago at a distance of around . Xi2 Ceti is a spectrophotometric standard star. It displays a stellar classification of B9.5III, which suggests it has exhausted its core hydrogen, evolved away from the main sequence, and expanded to become a giant star, although still only 127 million years old. It has 2.45 times the mass and 2.6 times the radius of the Sun. In Chinese, (), meaning '' Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mu Ceti
Mu Ceti (μ Ceti) is a star in the constellation Cetus. The combined apparent magnitude of the system is +4.27, and it is located 84 light-years from the Sun. In Chinese, (), meaning '' Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for Mu Ceti itself is "the Fourth Star of Circular Celestial Granary". Mu Ceti is an A9 giant star. It has been suspected to be a δ Scuti variable, but most studies find it to be of constant brightness. Three companions were all discovered during occultations of Mu Ceti by the Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of .... An orbit was derived for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Ceti
Lambda Ceti, Latinisation of names, Latinized from λ Ceti, is B-type star of fifth-magnitude located in the constellation Cetus. Historically, the star bore the traditional name Menkar, although today that name is more commonly associated with Alpha Ceti, α Ceti. This star, along with Alpha Ceti, α Cet (Menkar), Gamma Ceti, γ Cet (Kaffaljidhma), Delta Ceti, δ Cet, Mu Ceti, μ Cet, Xi1 Ceti, ξ1 Cet and Xi2 Ceti, ξ2 Cet were ''Al Kaff al Jidhmah'', "the Part of a Hand". In Chinese astronomy, Chinese, (), meaning ''Stomach (Chinese constellation), Circular Celestial Granary'', refers to an asterism consisting of λ Ceti, Alpha Ceti, α Ceti, Kappa1 Ceti, κ1 Ceti, Mu Ceti, μ Ceti, Xi1 Ceti, ξ1 Ceti, Xi2 Ceti, ξ2 Ceti, Nu Ceti, ν Ceti, Gamma Ceti, γ Ceti, Delta Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese star names, Chinese name for λ Ceti itself is (, en, the Third Star of Circular Celestial Granary.) Properties Lambda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kappa1 Ceti
Kappa1 Ceti, Latinized from κ1 Ceti, is a variable yellow dwarf star approximately 30 light-years away in the equatorial constellation of Cetus. The star was discovered to have a rapid rotation, roughly once every nine days. Though there are no extrasolar planets confirmed to be orbiting the star, Kappa1 Ceti is considered a good candidate to contain terrestrial planets, like the Earth. The system is a candidate binary star, but has not been confirmed. Description Kappa1 Ceti is a yellow dwarf star of the spectral type G5Vv. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. The star has roughly the same mass as the Sun, with 95% of the Sun's radius but only 85 percent of the luminosity. Its brightness varies by a few hundredths of a magnitude over a period of nine days and it is classified as a BY Draconis variable, a type of variable star where the brightness changes are due to spots on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Ceti
Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar , is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant about 250 light years away. Nomenclature ''Alpha Ceti'' is the star's Bayer designation. It has the traditional name Menkar, deriving from the Arabic word منخر ''manħar'' "nostril" (of Cetus). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Menkar'' for this star. This star, along with γ Cet (Kaffaljidhma), δ Cet, λ Cet (also Menkar), μ Cet, ξ1 Cet and ξ2 Cet were ''Al Kaff al Jidhmah'', "the Part of a Hand". In Chinese, (), meaning '' Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomach (Chinese Constellation)
The Stomach mansion (胃宿, pinyin: Wèi 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 .... Asterisms {{DEFAULTSORT:Stomach (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] |
White Dwarf
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name ''white dwarf'' was coined by Willem Luyten in 1922. White dwarfs are thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star or black hole. This includes over 97% of the other stars in the Milky Way. After the hydrogen- fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red giant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-process
The slow neutron-capture process, or ''s''-process, is a series of reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars. The ''s''-process is responsible for the creation (nucleosynthesis) of approximately half the atomic nuclei heavier than iron. In the ''s''-process, a seed nucleus undergoes neutron capture to form an isotope with one higher atomic mass. If the new isotope is stable, a series of increases in mass can occur, but if it is unstable, then beta decay will occur, producing an element of the next higher atomic number. The process is ''slow'' (hence the name) in the sense that there is sufficient time for this radioactive decay to occur before another neutron is captured. A series of these reactions produces stable isotopes by moving along the valley of beta-decay stable isobars in the table of nuclides. A range of elements and isotopes can be produced by the ''s''-process, because of the intervention of alpha decay steps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyano Radical
The cyano radical (or cyanido radical) is a radical with molecular formula CN, sometimes written •CN. The cyano radical was one of the first detected molecules in the interstellar medium, in 1938. Its detection and analysis was influential in astrochemistry. The discovery was confirmed with a coudé spectrograph, which was made famous and credible due to this detection. ·CN has been observed in both diffuse clouds and dense clouds. Usually, CN is detected in regions with hydrogen cyanide, hydrogen isocyanide, and HCNH+, since it is involved in the creation and destruction of these species (see also ''Cyanogen''). Physical Properties Bonding in the cyano radical can be described as a combination of two resonance structures: the structure with the unpaired electron on the carbon is the minor contributor, while the structure with the unpaired electron on the nitrogen (the isocyano radical) is the major contributor. The charge separation in the isocyano radical is similar to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
