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Hyades
Hyades , in astronomy, open star cluster in the constellation Taurus, located immediately to the right of the bright star Aldebaran. The cluster is about 130 light-years from the earth. It consists of about 100 stars all moving in the same direction. Its shape is that of an oblate spheroid, with most of the stars lying within 20 light-years of the center. Most of the stars in this cluster are of spectral class G and K and are average in size, with temperatures that are comparable to that of the sun. The nebular variable star T Tauri is part of this cluster. The Hyades is important as a fundamental calibration point in the distance scale of the universe. Because it is one of the closest of the open clusters, measurements of parallaxes of its stars as well as the relationship between the apparent and absolute magnitudes of some of its member stars yield similar distance results. In 1908 L. Boss discovered that the proper motions of all the Hyades stars were converging as an effect of perspective, and that their motions were really parallel. Once the convergent point for the cluster was established, the distance could be calculated. With the distance to this cluster known accurately, absolute magnitudes for its members could be determined. Thus the Hyades stars are used as calibration for similar stars in far more distant clusters. |
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"Hyades." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "Hyades." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-Hyad-ast.html "Hyades." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-Hyad-ast.html |
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Hyades
Hyades A large, V-shaped open cluster in Taurus, spanning over 5° of sky. It contains about 200 stars, and is estimated to be 660 million years old. The cluster lies 150 l.y. away, and its true diameter is about 15 l.y. Comparison of the brightness of its stars with those in other clusters enables the distances to those other clusters to be calculated. The Hyades is thus an important yardstick in astronomical measurement.
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"Hyades." A Dictionary of Astronomy. 1997. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "Hyades." A Dictionary of Astronomy. 1997. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O80-Hyades.html "Hyades." A Dictionary of Astronomy. 1997. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-Hyades.html |
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Hyades
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T. F. HOAD. "Hyades." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "Hyades." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O27-Hyades.html T. F. HOAD. "Hyades." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-Hyades.html |
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Hyades
Hyades
•Andes
•Hades, Mercedes
•Archimedes • Thucydides • aphides
•Eumenides, Parmenides
•Maimonides, Simonides
•Euripides • cantharides • Hesperides
•Hebrides
•Aristides, bona fides
•Culdees
•Alcibiades, Hyades, Pleiades
•Cyclades • antipodes • Sporades
•Ganges • Apelles
•tales, Thales
•Achilles, Antilles
•Los Angeles • Ramillies • Pericles
•isosceles • Praxiteles • Hercules
•Empedocles • Sophocles • Damocles
•Androcles • Heracles • Themistocles
•Hermes • Menes • testudines
•Diogenes • Cleisthenes
•Demosthenes
•Aristophanes, Xenophanes
•manganese • Holofernes • editiones principes • herpes
•lares, primus inter pares
•Antares, Ares, Aries, caries
•antifreeze • Ceres • Buenos Aires
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Cite this article
"Hyades." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "Hyades." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O233-Hyades.html "Hyades." Oxford Dictionary of Rhymes. 2007. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-Hyades.html |
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