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Gamma Ursae Minoris
Gamma Ursae Minoris (γ Ursae Minoris, abbreviated Gamma UMi, γ UMi), also named Pherkad , is a star in the northern constellation of Ursa Minor. Together with Beta Ursae Minoris (Kochab), it forms the end of the dipper pan of the "Little Dipper", which is an asterism forming the tail of the bear. Based upon parallax measurements obtained during the Hipparcos mission, it is approximately from the Sun. Nomenclature ''γ Ursae Minoris'' ( Latinised to ''Gamma Ursae Minoris'') is the star's Bayer designation. The fainter 11 Ursae Minoris has been called ''γ¹ Ursae Minoris'', in which case ''Gamma Ursae Minoris'' would be designated ''γ²''. However this usage is rarely seen. Gamma Ursae Minoris bore the traditional name ''Pherkad'', which derived from the Arabic فرقد ''farqad'' "calf", short for ''aḫfa al farkadayn'' "the dim one of the two calves", that is Pherkad and Kochab (the full name Ahfa al Farkadain is traditionally applied to Zeta Ursae Minoris). Gamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursa Minor (constellation)
Ursa Minor (Latin: 'Lesser Bear', contrasting with Ursa Major), also known as the Little Bear, is a constellation located in the far northern sky. As with the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, hence the North American name, Little Dipper: seven stars with four in its bowl like its partner the Big Dipper. Ursa Minor was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor has traditionally been important for navigation, particularly by mariners, because of Polaris being the north pole star. Polaris, the brightest star in the constellation, is a yellow-white supergiant and the brightest Cepheid variable star in the night sky, ranging in apparent magnitude from 1.97 to 2.00. Beta Ursae Minoris, also known as Kochab, is an aging star that has swollen and cooled to become an orange giant with an apparent magnitude of 2.08, only slightly fainter than Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ahfa Al Farkadain
Zeta Ursae Minoris, which is Latinized from ζ Ursae Minoris, is a single star in the northern circumpolar constellation of Ursa Minor, forming the northernmost part of the bowl in this "little dipper" asterism. The star has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.28. It is located at a distance of approximately 369 light-years from the Sun based on parallax, but is drifting further closer with a radial velocity of about –13 km/s. The stellar classification of Zeta UMi is A3Vn, a notation that indicates this is an A-type main-sequence star with broad "nebulous" absorption lines in its spectrum due to rapid rotation. Based on photometric data, some light variability was suspected by R. A. Baker in 1926, and it may be a Delta Scuti variable. It is a pulsating variable star, with a period of 15.8 hours, and it also undergoes eclipses. The star is spinning with a projected rotational velocity of 210 km/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Spectrum
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects. A stellar spectrum can reveal many properties of stars, such as their chemical composition, temperature, density, mass, distance and luminosity. Spectroscopy can show the velocity of motion towards or away from the observer by measuring the Doppler shift. Spectroscopy is also used to study the physical properties of many other types of celestial objects such as planets, nebulae, galaxies, and active galactic nuclei. Background Astronomical spectroscopy is used to measure three major bands of radiation in the electromagnetic spectrum: visible light, radio waves, and X-rays. While all spectroscopy looks at specific bands of the spectrum, different methods are required to acquire the signal depending on the frequency. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly , without Extinction (astronomy), extinction (or dimming) of its light due to absorption by Interstellar medium, interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. As with all astronomical magnitude (astronomy), magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified Filter (optics), filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bortle Dark-Sky Scale
The Bortle scale (also known as the Bottle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. John E. Bortle created the scale and published it in the February 2001 edition of ''Sky & Telescope'' magazine to help amateur astronomers evaluate the darkness of an observing site, and secondarily, to compare the darkness of observing sites. The scale ranges from Class 1, the darkest skies available on Earth, through to Class 9, inner-city skies. It gives several criteria for each level beyond naked-eye limiting magnitude (NELM). The accuracy and utility of the scale have been questioned in recent research. The table below summarizes Bortle's descriptions of the classes. Some classes can have very drastic differences from the one next to it, e.g, Bortle 4 to 5. In popular culture The band Days N' Daze referenced the scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, 6. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Star Name
Chinese star names (Chinese: , ''xīng míng'') are named according to ancient Chinese astronomy and astrology. The sky is divided into star mansions (, ''xīng xiù'', also translated as "lodges") and asterisms (, ''xīng guān''). The system of 283 asterisms under Three Enclosures and Twenty-eight Mansions was established by Chen Zhuo of the Three Kingdoms period, who synthesized ancient constellations and the asterisms created by early astronomers Shi Shen, Gan De and Wuxian. Since the Han and Jin Dynasties, stars have been given reference numbers within their asterisms in a system similar to the Bayer or Flamsteed designations, so that individual stars can be identified. For example, Deneb (α Cyg) is referred to as (''Tiān Jīn Sì'', the Fourth Star of Celestial Ford). In the Qing Dynasty, Chinese knowledge of the sky was improved by the arrival of European star charts. ''Yixiang Kaocheng'', compiled in mid-18th century by then deputy Minister of Rites Ignaz Kögler, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Σ 1694
Struve 1694 (Σ 1694, Struve 1694) is a double star in the constellation Camelopardalis. Σ 1694 is a double star, with components of magnitudes 5.3m and 5.9m: *Σ 1694A ( HD 112028) is a white A-type giant star with an apparent magnitude of 5.28m. It is approximately 300 light years from Earth. *Σ 1694B ( HD 112014) is a spectroscopic binary consisting of two A-type main sequence stars. Norton's Star Atlas describes the pair as yellowish and bluish. Σ 1694 was also known as 32H. Camelopardalis, Hevelius' 32nd of Camelopardalis. It is not Flamsteed's "32 Camelopardalis", which is ξ Aurigae. In the ''British Association Catalogue'', the star pair are listed as being in Ursa Minor. Chinese name In Chinese, (), meaning ''North Pole'', refers to an asterism consisting of Σ 1694, γ Ursae Minoris, β Ursae Minoris, 5 Ursae Minoris and 4 Ursae Minoris. Consequently, Σ 1694 itself is known as (, en, the Fifth Star of North Pole.), representing (), meaning ''C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4 Ursae Minoris
4 Ursae Minoris is a binary star system in the northern circumpolar constellation Ursa Minor. It is faintly visible to the naked eye with an apparent visual magnitude of 4.80. Based upon an annual parallax shift of as seen from Earth's orbit, it is located roughly 460 light years from the Sun. It is moving further away with a heliocentric radial velocity of +5.9 km/s. This is a single-lined spectroscopic binary star system with an orbital period of 1.66 years and an eccentricity of 0.14. The primary is a red giant of spectral type K3-IIIb Fe-0.5, a star that has used up its core hydrogen and is expanding. The suffix notation indicates the spectrum displays a mild underabundance of iron for a star of its type. It has expanded to around 28 times the Sun's radius and is radiating 437 times the 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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5 Ursae Minoris
5 Ursae Minoris is a star in the circumpolar constellation of Ursa Minor. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.253. The distance to this star, as determined from an annual parallax shift of , is about 110 pc. It is moving further away with a heliocentric radial velocity of +9 km/s. With an age of around two billion years, this is an evolved red giant with a stellar classification of K4-III; a star that has used up its core hydrogen and has expanded. It is a mild barium star, which may indicate it is a binary with a white dwarf companion, and is very lithium-weak. The star has an estimated 1.86 times the mass of the Sun and has expanded to about 16 times the Sun's radius. It is radiating 447 times the Sun's luminosity from its enlarged 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 amount of ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purple Forbidden Enclosure
The Purple Forbidden enclosure ( Zǐ wēi yuán) is one of the San Yuan ( Sān yuán) or Three Enclosures Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" ( Chinese ''xīng guān''). The Chinese asterisms are generally smaller than the constellations of Hellenistic .... Stars and constellations of this group lie near the north celestial pole and are visible all year from temperate latitudes in the Northern Hemisphere. Asterisms The asterisms are : See also * Twenty-eight mansions References Chinese constellations Chinese astrology {{china-stub ... [...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] |
