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Epsilon Ophiuchi
Epsilon Ophiuchi or ε Ophiuchi, formally named Yed Posterior (), is a red giant star in the constellation of Ophiuchus. Located less than five degrees south of the celestial equator in the eastern part of the constellation, it forms a naked eye optical double with Delta Ophiuchi (named ''Yed Prior''). With an apparent visual magnitude of 3.220, the star can be seen with the naked eye from most of the Earth under suitably dark skies. Parallax measurements yield an estimated distance of from the Sun. Nomenclature ''ε Ophiuchi'' ( Latinised to ''Epsilon Ophiuchi'') is the star's Bayer designation. It bore the traditional name ''Yed Posterior''. ''Yed'' derives from the Arabic يد ''yad'' meaning "hand". ''Epsilon'' and ''Delta Ophiuchi'' comprise the left hand of Ophiuchus (the Serpent Bearer) that holds the head of the serpent (Serpens Caput). ''Epsilon'' is ''Yed Posterior'' as it follows ''Delta '' across the sky. In 2016, the International Astronomical Union organiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiuchus
Ophiuchus () is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek (), meaning "serpent-bearer", and it is commonly represented as a man grasping a snake. The serpent is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. An old alternative name for the constellation was Serpentarius (). Location Ophiuchus lies between Aquila, Serpens, Scorpius, Sagittarius, and Hercules, northwest of the center of the Milky Way. The southern part lies between Scorpius to the west and Sagittarius to the east. In the northern hemisphere, it is best visible in summer. It is opposite of Orion. Ophiuchus is depicted as a man grasping a serpent; the interposition of his body divides the snake constellation Serpens into two parts, Serpens Caput and Serpens Cauda. Ophiuchus straddles the equator with the majority ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAU Working Group On Star Names
The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education, Outreach and Heritage. The IAU states that it is keen to make a distinction between the terms ''name'' and ''designation''. To the IAU, ''name'' refers to the (usually colloquial) term used for a star in everyday conversation, while ''designation'' is solely alphanumerical, and used almost exclusively in official catalogues and for professional astronomy. (The WGSN notes that transliterated Bayer designations (e.g., Tau Ceti) are considered a special historical case and are treated as designations.) Terms of reference The terms of reference for the WGSN for the period 2016–2018 were approved by the IAU Executive Committee at its meeting on 6 May 2016. In summary, these are to: * establish IAU guidelines for the proposal and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Serpentis
Beta Serpentis, Latinized from β Serpentis, is a binary star system in the constellation Serpens, in its head (Serpens Caput). It is visible to the naked eye with a combined apparent visual magnitude of +3.65. Based upon an annual parallax shift of 21.03 mas as seen from Earth, it is located around 155 light years from the Sun. The system is a member of the Ursa Major Moving Group. Components The visual magnitude +3.68 primary, component A, is either an ordinary A-type main-sequence star or somewhat evolved subgiant with a stellar classification of A2 V or A2 IV, respectively. The star is about 267 million years old with nearly double the mass of the Sun. It is spinning rapidly with a projected rotational velocity of 207 km/s. The secondary component, visual magnitude 9.7 B, lies at an angular separation of 30.6 arc seconds. It is a main-sequence star with a class of K3 V. There is a magnitude +10.98 visual companion, designated com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Serpentis
Gamma Serpentis (γ Serpentis, γ Ser) is a star in the equatorial constellation Serpens, in the part of the constellation that represents the serpent's head (Serpens Caput). It has an apparent visual magnitude +3.85, which means it is visible to the naked eye. Based upon parallax measurements by the Hipparcos spacecraft, this star is approximately 36.7 light years from Earth. Properties Gamma Serpentis is an ordinary F-type main sequence star with a stellar classification of F6 V. It is larger and more massive than the Sun, with three times the solar luminosity. Based upon its mass, it may have a convection zone in its core region. The projected rotational velocity along the equator is 10.2 km/s. It is younger than the Sun with an estimated age of 3.5 billion years. The effective temperature of the star's outer atmosphere is 6,350 K, giving it the yellow-white-hued glow of an F-type star. Occasionally Gamma Serpentis is listed as having two 10th magnitud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kappa Herculis
Kappa Herculis (κ Herculis, abbreviated Kappa Her, κ Her) is an optical double star in the constellation of Hercules. The two components, Kappa Herculis A (Marsic , the traditional name of the system) and B, were 27.3 arc seconds apart in 2000. Based on parallax measurements from the Hipparcos mission, κ Her A is about 113 parsecs (370 light-years) from the Sun and κ Her B is 600 parsecs (2,000 light-years); more recent parallax measurements suggest that B is around 5% more distant than A. A faint third component Kappa Herculis C is just over 1 arc-minute away. It is at the same distance as κ Her A and has an almost-identical space motion. The star 8 Herculis forms a naked eye pair with Kappa Herculis away. Nomenclature κ Herculis ( Latinised to ''Kappa Herculis'') is the system's Bayer designation. The designations of the components as ''Kappa Herculis A'', ''B'' and ''C'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Herculis
Gamma Herculis, Latinized from γ Herculis, is a magnitude 3.74 binary star system in the northern constellation of Hercules. Properties This is known to be a spectroscopic binary system, although there is no information about the secondary component. Based upon parallax measurements, this system is located at a distance of about from the Earth. The spectrum of the primary star matches a stellar classification of A9III, which indicates this is a giant star that has exhausted the hydrogen at its core and evolved away from the main sequence. The effective temperature is about 7,031 K, giving the star a white hue characteristic of A-type stars. It is rotating rapidly with a projected rotational velocity of . The interferometry-measured angular diameter of this star is , which, at its estimated distance, equates to a physical radius of about six times the radius of the Sun. Observations by German astronomer Ernst Zinner in 1929 gave indications that this may be a varia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Herculis
Beta Herculis (β Herculis, abbreviated Beta Her, β Her), formally named Kornephoros , or Rutilicus, is a binary star and the brightest star in the northern constellation of Hercules at a base apparent visual magnitude of 2.81. This is a suspected variable star with an apparent magnitude that may rise as high as 2.76. Based upon parallax measurements, it is located at a distance of from the Sun. Although Beta Herculis appears to the naked eye to be a single star, in July 1899 the American astronomer W. W. Campbell discovered from spectroscopic measurements that its radial velocity varies, and concluded that it has a companion. Properties At Palomar Observatory, Antoine Labeyrie and others used speckle interferometry with the Hale Telescope to resolve the system in 1977. The Hipparcos satellite observed the orbital motion of the primary relative to other stars, and an orbit was computed in 2005 using spectroscopic data together with these measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heavenly Market Enclosure
The Heavenly Market Enclosure (天市垣, ''Tian Shi Yuan''), is one of the ''San Yuan'' 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 are visible during late summer and early autumn in the Northern Hemisphere (late winter and early spring in the Southern). The Summer Triangle lies directly to the northeast. Asterisms The asterisms are : See also * Twenty-eight mansions * Summer Triangle Chinese constellations {{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] |
Gamma Ophiuchi
Gamma Ophiuchi, Latinized from γ Ophiuchi, is a fourth-magnitude star in the constellation Ophiuchus. Together with Beta Ophiuchi, it forms the serpent-holder's right shoulder. The staris visible to the naked eye with an apparent visual magnitude of +3.75. Based upon an annual parallax shift of as seen from Earth, it is located 103 light years from the Sun. It is moving closer to the Sun with a radial velocity of −7.6 km/s. It is known also as Muliphen, although at least two more stars are known with this name: Gamma Canis Majoris (often spelled as Muliphein) and Gamma Centauri (often spelled as Muhlifain). This is an A-type main sequence star with a stellar classification of A0 V. Gray et al. (2003) lists a classification of A1VnkA0mA0, indicating it is of type A1 V with the calcium K-line and metallic lines of an A0 star. It is approximately 184 million years old and is spinning rapidly with a projected rotational velocity of 220 km/s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta Ophiuchi
Zeta Ophiuchi (ζ Oph, ζ Ophiuchi) is a single star located in the constellation of Ophiuchus. It has an apparent visual magnitude of 2.6, making it the third-brightest star in the constellation. Parallax measurements give an estimated distance of roughly from the Earth. It is surrounded by the Sh2-27 "Cobold" nebula, the star's bow shock as it ploughs through dense dust clouds near the Rho Ophiuchi cloud complex. In April 2010, Zeta Ophiuchi was occulted by asteroid 824 Anastasia. Properties ζ Ophiuchi is an enormous star with more than 19 times the Sun's mass and eight times its radius. The stellar classification of this star is O9.5 V, with the luminosity class of V indicating that it is generating energy in its core by the nuclear fusion of hydrogen. From Earth, the apparent effective temperature of the star appears to be 34,300K, giving the star the blue hue of an O-type star. However, since the star is rapidly rotating, the exact surface temperature varies acr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Serpentis
Epsilon Serpentis, Latinized from ε Serpentis, is a single, white-hued star in the constellation Serpens, in its head (Serpens Caput). It is visible to the naked eye with an apparent visual magnitude of +3.69. Based upon an annual parallax shift of 46.30 mas as seen from Earth, it is located 70 light years from the Sun. It is moving closer to the Sun with a radial velocity of −9 km/s. This is an Am star on the main-sequence with a stellar classification of kA2hA5mA7 V. This notation indicates the spectrum displays the calcium K-line of an A2 star, the hydrogen lines of an A5 star, and the metal lines of an A7 star. It has been examined for the presence of a magnetic field, but the detected level was not statistically significant. Epsilon Serpentis has an estimated 1.82 times the mass of the Sun and 1.78 times the Sun's radius. The star is radiating 12 times the Sun's luminosity from its photosphere at an effective temperature of around 7,928 K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
