|
Tau Eridani
Tau Eridani (τ Eridani, τ Eri) is a group of fairly widely scattered stars in the constellation Eridanus. They form an exception to the general rule that stars that share the same Bayer designation are close together: τ1 is nearly 20° away from τ9 (Pi Orionis is another example of this). * τ1 Eridani (1 Eridani) * τ2 Eridani (2 Eridani) * τ3 Eridani (11 Eridani) * τ4 Eridani (16 Eridani) * τ5 Eridani (19 Eridani) * τ6 Eridani (27 Eridani) * τ7 Eridani (28 Eridani) * τ8 Eridani (33 Eridani) * τ9 Eridani (36 Eridani) All of them were member of asterism 天苑 (Tiān Yuàn), ''Celestial Meadows'', ''Hairy Head The Hairy Head mansion (昴宿, pinyin: Mǎo Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger. This mansion corresponds to the Pleiades The Pleiades (), also kno ...'' mansion. See also * Map analysis of the 1961 Zeta Reticuli Incident References {{Set index art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sky, night, but their immense distances from Earth make them appear as fixed stars, fixed points of light. The most prominent stars have been categorised into constellations and asterism (astronomy), asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life star formation, begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its stellar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellations likely go back to prehistory. People used them to relate stories of their beliefs, experiences, creation myth, creation, or mythology. Different cultures and countries adopted their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. The recognition of constellations has changed significantly over time. Many changed in size or shape. Some became popular, only to drop into obscurity. Some were limited to a single culture or nation. The 48 traditional Western constellations are Greek. They are given in Aratus' work ''Phenomena'' and Ptolemy's ''Almagest'', though their origin probably predates these works by several centuries. Constellation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eridanus (constellation)
Eridanus () is a constellation in the southern celestial hemisphere. It is represented as a river. One of the 48 constellations listed by the 2nd century astronomer Ptolemy, it remains one of the 88 modern constellations. It is the sixth largest of the modern constellations, and the one that extends farthest in the sky from north to south. The same name was later taken as a Latin name for the real Po River and also for the name of a minor river in Athens. Features Stars At its southern end is the magnitude 0.5 star Achernar, designated Alpha Eridani. It is a blue-white hued main sequence star 144 light-years from Earth, whose traditional name means "the river's end". Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. This distortion occurs because the star is spinning extremely rapidly. There are several other noteworthy stars in Eridanus, including ... [...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] |
Pi Orionis
Pi Orionis (π Ori, π Orionis) is a group of fairly widely scattered stars in the constellation Orion that constitute the asterism Orion's Shield or Orion's Bow.astrofoto.org"Orion: The Hunter", Roland B. Roberts They form an exception to the general rule that stars that share the same Bayer designation are close together: π1 is nearly 9° north of π6 ( Tau Eridani is an even more noteworthy example of this). * π1 Ori (''7 Orionis'') * π2 Ori (''2 Orionis'') * π3 Ori (''1 Orionis'') * π4 Ori (''3 Orionis'') * π5 Ori (''8 Orionis'', forms a visual double with ''5 Orionis'') * π6 Ori (''10 Orionis'') All of them were member of asterism 參旗 (Shēn Qí), ''Banner of Three Stars'', ''Net'' mansion. See also *Orion's Belt *Orion's Sword Orion's Sword is a compact asterism in the constellation Orion. It comprises three stars (42 Orionis, Theta Orionis, and Iota Orionis) and M42, the Orion Nebula, which together are thought to resemble a sword or its scabbar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau1 Eridani
Tau1 Eridani, Latinized from τ1 Eridani, is a binary star system in the constellation Eridanus. It has an apparent magnitude of 4.46, making it visible to the naked eye in suitably dark conditions. This a spectroscopic binary with an orbital period of 958 days. It is located about 46 light years from the Earth. At present, the system is moving away from the Sun with a radial velocity of +26 km/s. About 305,000 years ago, it made perihelion passage at an estimated distance of . Tau1 Eridani was a latter designation of 90 Ceti. Debris disk A moderate far-infrared excess was observed for this star system, in the 12μm, 25μm, 60μm and 100μm wavelengths, by the Infrared Astronomical Satellite (IRAS), and published in 1993. This discovery was subsequently interpreted as indicating a debris disk with a radius near to 500 AU. It was further speculated that, if the star system had been observed at longer wavelengths, it was likely the debris disk would have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau2 Eridani
Tau2 Eridani (τ2 Eridani, abbreviated Tau2 Eri, τ2 Eri), formally named Angetenar , is a star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.78. The distance to this star, as determined via the parallax method, is around 187 light-years. Nomenclature ''τ2 Eridani'' ( Latinised to ''Tau2 Eridani'') is the system's Bayer designation. It is one of a series of stars that share the Bayer designation Tau Eridani. It bore the traditional name ''Angetenar'', derived from the Arabic ''Al Ḥināyat an-Nahr'', 'the Bend in the River', near which it lies. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name ''Angetenar'' for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names. In Chinese, (), meaning '' Celestial Meadows'', refers to an asterism consisting of Tau2 Eridani, Gamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau3 Eridani
Tau3 Eridani, Latinized from τ3 Eridani, is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.10. Using the parallax method, the distance to this star can be estimated as 88.6 light years. In 2001 it was reported as a candidate Vega-like star, meaning it appears to radiate an infrared excess from an orbiting circumstellar disk. However, this has not been confirmed. This is an A-type star with a stellar classification of A3 IV-V. The luminosity class of IV-V indicates the spectrum displays traits intermediate between a main sequence and subgiant star. It is around 476 million years old and is spinning rapidly with a projected rotational velocity of 133 km/s. This is creating an equatorial bulge that might be 7% wider than the polar radius. Tau3 Eridani has 178% of the Sun's mass and nearly double the radius of the Sun. The star shines with 13.7 times the solar luminosity from an outer at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau4 Eridani
Tau4 Eridani (τ4 Eridani, τ4 Eri) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.65. The distance to this star can be estimated using the parallax method, which yields a value of roughly 300 light years. This is an evolved red giant star currently on the asymptotic giant branch with a stellar classification of M3/4 III. It is a slow irregular variable star of type Lb, undergoing changes in magnitude over the range 3.57−3.72 with a periodicity of 23.8 d. The measured angular diameter of Tau4 Eridani is . At its estimated distance, this yields a physical size of about 106 times the radius of the Sun. It shines with 1,537 times the luminosity of the Sun from an outer atmosphere at an effective temperature of 3,712 K. This is most likely a binary star system. The companion is a magnitude 9.5 star at an angular separation of 5.7 ″ along a position angle of 291°, as of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau5 Eridani
Tau5 Eridani, Latinized from τ5 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.26. The distance to this system, as estimated using the parallax technique, is around 293 light years. Tau5 Eridani is a double-lined spectroscopic binary system. The two stars orbit each other closely with a period of 6.2 days and an eccentricity of 0.2. On average, the two stars are separated by around 0.183 AU. The primary component is a B-type main sequence star with a stellar classification of B0 V. It is around 157 million years old and is spinning with a projected rotational velocity of 55 km/s. The star has around 3.3 times the mass of the Sun and 3.2 times the Sun's radius. It radiates 188 times the solar luminosity from an outer atmosphere at an effective temperature of 12,514 K. The secondary component has a stellar classification of B9&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau6 Eridani
Tau6 Eridani, Latinized from τ6 Eridani, is a single star in the equatorial constellation of Eridanus, located near the constellation border with Fornax. It has a yellow-white hue with an apparent visual magnitude of 4.22, which is bright enough to be seen with the naked eye. Based upon parallax measurements, the distance to this star is around 57.5 light years. It is drifting further away with a radial velocity of +8 km/s. The spectrum of Tau6 Eridani matches a stellar classification of F5IV-V, indicating it is an F-type star that shows traits of both a main sequence star and a subgiant. It has an estimated 135% of the Sun's mass and about 1.8 time the radius of the Sun. The star is radiating 5.5 times the luminosity of the Sun at an effective temperature of 6,508 K, and it does not display any surface magnetic activity. The star has been examined for infrared excess emission that could indicate the presence of circumstellar matter, but none ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tau7 Eridani
Tau7 Eridani is a solitary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 5.235. Using the parallax method, the distance to this star can be estimated as around 251 light years. This is an A-type main sequence star with a stellar classification of A3 Vs, where the 's' indicates it has narrow absorption lines. It may be a chemically peculiar Am star, which means it displays unusual abundances of certain elements in its surface layers. Tau7 Eridani appears to be a low amplitude variable that displays slight fluctuations in luminosity over a period of 7.17 days. It is slowly rotating with a projected rotational velocity of 18 km/s, and is around 387 million years old. References {{DEFAULTSORT:Tau7 Eridani A-type main-sequence stars Eridanus (constellation) Eridani, Tau7 Eridani, 28 023878 017717 1181 Year 1181 ( MCLXXXI) was a common year starting on Thursday (link will disp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
