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γ Pyxidis
Gamma Pyxidis, Latinized from γ Pyxidis, is a single, orange-hued star in the southern constellation Pyxis. It is visible to the naked eye, having an apparent visual magnitude of 4.010. Based upon an annual parallax shift of 15.73 mas as seen from Earth, it is located about 207 light years from the Sun. The star is moving further from the Sun with a radial velocity of +24.5 km/s. Properties This is an evolved K-type giant star with a stellar classification of K3 III. It is a red clump star on the horizontal branch, indicating that it is generating energy through helium fusion at its core. The composition of the stellar atmosphere is similar to the Sun, having roughly the same abundance of iron in its spectrum. The star has an estimated 1.64 times the mass of the Sun and has expanded to nearly 22 times the Sun's radius. At the age of around four billion years, it is radiating 178 times the Sun's luminosity from its enlarged photosphere at an ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyxis
Pyxis is a small and faint constellation in the southern sky. Abbreviated from Pyxis Nautica, its name is Latin for a mariner's compass (contrasting with Circinus, which represents a draftsman's compasses). Pyxis was introduced by Nicolas-Louis de Lacaille in the 18th century, and is counted among the 88 modern constellations. The Galactic plane, plane of the Milky Way passes through Pyxis. A faint constellation, its three brightest stars—Alpha Pyxidis, Alpha, Beta Pyxidis, Beta and Gamma Pyxidis—are in a rough line. At magnitude 3.68, Alpha is the constellation's brightest star. It is a blue-white star approximately distant and around 22,000 times as luminosity, luminous as the Sun. Pyxis is located close to the stars that formed the old constellation Argo Navis, the ship of Jason and the Argonauts. Parts of Argo Navis were the Carina (the keel or hull), the Puppis (the stern), and the Vela (the sails). These eventually became their own constellations. In the 19th century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Atmosphere
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. Overview The stellar atmosphere is divided into several regions of distinct character: * The photosphere, which is the atmosphere's lowest and coolest layer, is normally its only visible part. Light escaping from the surface of the star stems from this region and passes through the higher layers. The Sun's photosphere has a temperature in the range. Starspots, cool regions of disrupted magnetic field, lie in the photosphere. * Above the photosphere lies the chromosphere. This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. * Above the chromosphere lies the transition region, where the temperature increases rapidly on a distance of only around . * Additionally, many stars have a molecular layer (MOLsphere) above the photosphere and just beyond or even within the chromosphe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta Pyxidis
Delta Pyxidis (δ Pyxidis) is binary star system in southern constellation of Pyxis. Having an apparent visual magnitude of +4.877, it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 13.19 mas as seen from Earth, it is located around 250 light years from the Sun. In Chinese, (), meaning '' Celestial Dog'', refers to an asterism consisting of δ Pyxidis, e Velorum, f Velorum, β Pyxidis, α Pyxidis and γ Pyxidis. Consequently, δ Pyxidis itself is known as (, .) This is an astrometric bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Pyxidis
Alpha Pyxidis, Romanization of Greek, Latinised from α Pyxidis, is a giant star in the constellation Pyxis. It is the brightest star in Pyxis, and is easily visible to the naked eye. It has a stellar classification of B1.5III and is a Beta Cephei variable. This star has more than ten times the mass of the Sun and is more than six times the Sun's radius. The surface temperature is and the star is about 10,000 times as Solar luminosity, luminous as the Sun. Stars such as this with more than 10 solar masses are expected to end their life by exploding as a supernova. Naming In Chinese language, Chinese, (), meaning ''Ghost (Chinese constellation), Celestial Dog'', refers to an Asterism (astronomy), asterism consisting of α Pyxidis, HD 73634, e Velorum, KX Velorum, f Velorum, β Pyxidis, γ Pyxidis and δ Pyxidis. Consequently, α Pyxidis itself is known as (, ). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Pyxidis
Beta Pyxidis, Latinized from β Pyxidis, is a double star located in the southern constellation Pyxis. It has an apparent visual magnitude of 3.954, making it the second brightest star in that faint constellation. Based upon parallax measurements, the star is an estimated 420 light-years (128 parsecs) from the Earth. The spectrum matches a bright giant or giant star of stellar classification G7II-III. It has 3.8 times the mass of the Sun but has expanded to 20 times the Sun's radius. The effective temperature of the star's outer envelope is about 5,283 K, giving it the characteristic yellow hue of a G-type star. Beta Pyxidis has an unusually high rate of spin for an evolved star of this type, showing a projected rotational velocity of 11.8 km/s. One possible explanation is that it may have engulfed a nearby giant planet, such as a hot Jupiter. In 2010, the star was among a survey of massive, lower effective temperature supergiants in an at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F Velorum
F, or f, is the sixth letter of the Latin alphabet and many modern alphabets influenced by it, including the modern English alphabet and the alphabets of all other modern western European languages. Its name in English is ''ef'' (pronounced ), and the plural is ''efs''. History The origin of ⟨F⟩ is the Semitic letter '' waw'', which represented a sound like or . It probably originally depicted either a hook or a club. It may have been based on a comparable Egyptian hieroglyph such as that which represented the word ''mace'' (transliterated as ḥ(dj)): T3 The Phoenician form of the letter was adopted into Greek as a vowel, ''upsilon'' (which resembled its descendant ⟨ Y⟩ but was also the ancestor of the Roman letters ⟨ U⟩, ⟨ V⟩, and ⟨ W⟩); and, with another form, as a consonant, ''digamma'', which indicated the pronunciation , as in Phoenician. Latin ⟨F⟩, despite being pronounced differently, is ultimately descended from digamma and closely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E Velorum
The Bayer designations e Velorum and E Velorum are distinct. Due to technical limitations, both designations link here. For the star *e Velorum, see HD 73634 HD 73634 is a single star in the southern constellation of Vela. It has the Bayer designation e Velorum; ''HD 73634'' is the star's designation from the ''Henry Draper Catalogue''. The star is white in hue and is faintly visible to the n ... *E Velorum, see HV Velorum (HD 73340) {{Set index article, astronomical objects Velorum, e Vela (constellation) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghost (Chinese Constellation)
The Ghost mansion () is one of the Twenty-eight mansions of the Chinese constellations. It is one of the southern mansions of the Vermilion Bird The Vermilion Bird ( zh, c=朱雀, p=Zhūquè) is one of the Four Symbols of the Chinese constellations. According to Wuxing (Chinese philosophy), Wu Xing, the Taoism, Taoist five elemental system, it represents the Fire (Wu Xing), Fire element, .... Asterisms {{DEFAULTSORT:Ghost (Chinese Constellation) Chinese constellations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Language
Chinese ( or ) is a group of languages spoken natively by the ethnic Han Chinese majority and List of ethnic groups in China, many minority ethnic groups in China, as well as by various communities of the Chinese diaspora. Approximately 1.39 billion people, or 17% of the global population, speak a variety of Chinese as their first language. Chinese languages form the Sinitic languages, Sinitic branch of the Sino-Tibetan language family. The spoken varieties of Chinese are usually considered by native speakers to be dialects of a single language. However, their lack of mutual intelligibility means they are sometimes considered to be separate languages in a Language family, family. Investigation of the historical relationships among the varieties of Chinese is ongoing. Currently, most classifications posit 7 to 13 main regional groups based on phonetic developments from Middle Chinese, of which the most spoken by far is Mandarin Chinese, Mandarin with 66%, or around 800&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun's Luminosity
The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This corresponds almost exactly to a bolometric absolute magnitude of +4.74. The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the solar constant). Slow changes in the axial tilt of the planet and the shape of its orbit cause cyclical changes to the solar irradiance. The result is orbital forcing that causes the Milankovitch cycles, which determine Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
