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Mira |
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Mira (mī`rə), [Lat.,=marvelous], variable star variable star, star that varies, either periodically or irregularly, in the intensity of the light it emits. Other physical changes are usually correlated with the fluctuations in brightness, such as pulsations in size, ejection of matter, and changes in spectral
..... Click the link for more information. in the constellation Cetus; Bayer designation Omicron Ceti; 1992 position R.A. 2h19.0m, Dec. −3°05'. The most famous long-period variable, Mira ranges in apparent magnitude magnitude, in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. A.D.), all visible with the unaided eye, were ranked on a brightness scale such that the brightest stars were of 1st magnitude and the ..... Click the link for more information. from a maximum of about 2.0 to a minimum of about 10.1 with a period of a little less than a year (332 days). Thus, it is visible to the naked eye for about half a year and can be seen only through a telescope for the remainder of its period. Mira is of spectral class spectral class, in astronomy, a classification of the stars by their spectrum and luminosity. In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically. ..... Click the link for more information. M6e III, the spectrum showing some emission lines. There is some variation in maximum brightness that is thought to be due to clouds of hydrogen gas surrounding the star. Mira's distance from the earth is about 100 light-years. Mira [′mir·ə] (astronomy) The first star recognized to be a periodic variable; has a period of 332 ± 9 days and its spectrum changes from M5e at maximum to M9e at minimum;it is the prototype of long-period variable stars. Mira (o Ceti), the first known variable star; discovered as a variable star in 1596 by D. Fabricius. Mira varies in brightness from a stellar magnitude of 2.0 to a stellar magnitude of 10.1, with a period averaging 331.5 days. The variations in brightness are due to the pulsations of the star, as a result of which the diameter varies by approximately 10 percent, which is accompanied by a variation in the temperature and brightness of the star’s surface. Mira measures about 500 million km in diameter and is located 77 parsecs from the sun. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
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