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Gamma Sagittae
Gamma Sagittae, Latinized from γ Sagittae, is the brightest star in northern constellation of Sagitta. A single star, it is visible to the naked eye with an apparent visual magnitude of +3.47. Based upon an annual parallax shift of 12.62 mas as seen from Earth, it is located about 288 light-years from the Sun. It is moving closer to the Sun with a radial velocity of −34 km/s. This is a red giant star with a stellar classification of M0 III. It is most likely (94% chance) on the red-giant branch of its evolutionary lifespan, fusing hydrogen along a shell to generate energy. The star is around 2.35 billion years old with roughly 55 times the Sun's radius. Mass estimates range from 0.9 to 1.8 times the mass of the Sun. It is radiating about 562 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,862 K. Naming In Chinese, (), meaning '' Left Flag'', refers to an asterism consisting of γ Sagittae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas ''Uranometria''. Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers (including Nicolas-Louis de Lacaille and Benjamin Apthorp Gould) supplemented Bayer's catalog with entries for southern constellations. Scheme Bayer assigned a lowercase Greek letter (alpha (α), beta (β), gamma (γ), etc.) or a Latin letter (A, b, c, etc.) to each star he catalogued, combined with the Latin name of the star's parent constellation in genitive (possessive) form. The constellation name is frequently abbreviated to a standard three-letter form. For example, Aldebaran in the constellation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fusion
Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles ( neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released. A nuclear fusion process that produces atomic nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have a relatively small mass and a relatively large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while the fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is endo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
11 Sagittae
11 Sagittae is a star in the constellation Sagitta. It is a blue giant with a spectral classification of B9III and has evolved off the main sequence. The star will enter the Hertzsprung gap soon. Naming It is in the Chinese asterism (), or '' Left Flag'' which consists of 11 Sagittae, γ Sagittae, α Sagittae, β Sagittae, δ Sagittae, ζ Sagittae, 13 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are often a ... for γ Sagittae itself is (, en, the Seventh Star of Left Flag). References {{Stars of Sagitta B-type giants Sagitta (constellation) Sagittae, 11 189090 7622 098324 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
13 Sagittae
13 Sagittae is a single star in the northern constellation of Sagitta. The designation comes from the star catalogue of John Flamsteed, first published in 1712. It can be viewed with the naked eye, having an apparent visual magnitude of 5.33. Based upon an annual parallax shift of 5.94 mas as seen from Earth's orbit, it is located at a distance of around . It is moving closer to the Sun with a heliocentric radial velocity of −17.56 km/s. This is an evolved red giant with a stellar classification of M4 III – a star that has used up its core hydrogen and has expanded – and is currently on the asymptotic giant branch. Classified as a semiregular variable and given the variable star designation VZ Sagittae, it varies between apparent magnitudes 5.27 and 5.57. The measured angular diameter, after correction for limb darkening, is . At its estimated distance, this yields a physical size of about 60 times the radius of the Sun. There is a magnitude 9.96 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ζ Sagittae
Zeta Sagittae (ζ Sagittae) is triple star system in the northern constellation of Sagitta. It is visible to the naked eye, having a combined apparent visual magnitude of +5.00. Based upon an annual parallax shift of , the distance to this star is approximately . The inner pair is a visual binary system consisting of two A-type main-sequence stars with an orbital period of , a semimajor axis of 0.136 arc seconds, and an eccentricity of 0.79. The primary, component A, has a visual magnitude of 5.64 with a stellar classification of A3 Vnn, where the 'nn' suffix indicates "nebulous" lines due to rotation. It is spinning rapidly with a projected rotational velocity of . This is giving the star an oblate shape with an equatorial bulge that is 14% larger than the polar radius. The secondary member, component B, is a magnitude 6.04 star, while the more distant component C is magnitude 9.01 and lies at an angular separation of from the other two. Naming In Chine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
δ Sagittae
Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main-sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax. Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected. It has an orbital period of about 10 years and an eccentricity of about 0.44. It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way. Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy. Naming In Chinese, (), meaning '' Left Flag'', refers to an asterism consisting of δ Sagittae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β Sagittae
Beta Sagittae, Latinized from β Sagittae, is a single star in the northern constellation of Sagitta. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.38. Based upon an annual parallax shift of 7.7237 mas as seen from the Gaia satellite, it is located 420 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −22 km/s. This is an evolved red giant with a stellar classification of . The suffix notation indicates a mild overabundance of the cyanogen molecule in the spectrum. Beta Sagittae is an estimated 129 million years old with 4.33 times the mass of the Sun, and has expanded to roughly 27 times the Sun's radius. The star is radiating 392 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,850 K. Naming In Chinese, (), meaning '' Left Flag'', refers to an asterism consisting of β Sagittae, α Sagittae, δ Sagittae, ζ Sagittae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α Sagittae
Alpha Sagittae, formally named Sham , is a single star in the northern constellation of Sagitta. ''Alpha Sagittae'' is the Bayer designation, which is latinized from α Sagittae and abbreviated Alpha Sge or α Sge. It is visible to the naked eye as a yellow-hued star with an apparent visual magnitude of +4.38. Despite the name, this is not the brightest star in the constellation – that distinction belongs to Gamma Sagittae. Based upon parallax measurements, Alpha Sagittae is approximately 382 light-years from the Sun. It is moving further away from the Earth with a heliocentric radial velocity of 1.7 km/s. This is an evolved bright giant with a stellar classification of G1 II. It is 151 million years old with 4 times the mass of the Sun and has expanded to around 21 times the Sun's radius. It is radiating 340 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,333 K. There is an X-ray source within o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ox (Chinese Constellation)
The Ox mansion (牛宿, pinyin: Niú Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise. The primary asterism of this mansion is centered on the tail of the constellation known as Capricornus Capricornus is one of the constellations of the zodiac. Its name is Latin for "horned goat" or "goat horn" or "having horns like a goat's", and it is commonly represented in the form of a sea goat: a mythical creature that is half goat, half f ... in Western astronomy. Asterisms References {{DEFAULTSORT:Ox (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] |
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, including 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 straightf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. The term itself 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. 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 deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. 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. Composition of the Sun The Sun is composed primarily of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
