61. Binary Stars - Hutchinson Encyclopedia Article About Binary Stars binary star. Pair of stars moving in orbit around their common centre of mass. Observations show that most stars are binary, or even multiple – for example, the nearest star http://encyclopedia.farlex.com/Binary stars

62. Decatur Area Astronomy Club - Binary Stars Binary Stars. Looking through a telescope at the stars there is very little information we can gain from them. To be sure, we know what color they are and we can see that some http://www.decaturastronomy.com/binary.htm

Binary Stars Looking through a telescope at the stars there is very little information we can gain from them. To be sure, we know what color they are and we can see that some are more luminous than others. If we use a spectrograph we can tell what elements they are made up from. From these facts alone, it is difficult to tell just how much mass they contain. By looking at pairs of stars that orbit one another we can try to answer the question, how much mass do the stars have? Binary stars can be of two fundamental types: Visual Binaries Optical Doubles Visual Binaries are stars that are clearly gravitationally associated with one another. They orbit each other around a common center called the barycenter . Visual binaries can be seen optically through a telescope. Only a small portion of binary stars are visual binaries. In order to see a visual binary, the stars must be separated by fairly wide distances, and the orbital periods are usually very long. Optical Doubles are stars that appear to lie close together, but in fact do not, they only appear to us from our earthly observation to be close together. One of the stars in the pair is actually behind the first star and very far away. The stars of an optical double are not gravitationally bound. William Herschel began looking for optical doubles in 1782 with the hope that he would find a measurable parallax, by comparing a close star to the more distant star in an optical double.

63. Astronomy Cast - Ep. 152: Binary Stars Take a weekly factsbased journey through the cosmos with Astronomy Cast. http://www.astronomycast.com/astronomy/ep-152-binary-stars/

64. Binary Stars What is a Binary Star? A binary star is defined as a stellar system which is composed of two stars orbiting one another about their common center of mass. http://library.thinkquest.org/C007410/ie4/stars/binary.shtml

Search Sitemap Glossary Customize ... Forum STARS [an error occurred while processing this directive] MENU HOME PAGE HISTORY OF COSMOLOGY ASTRONOMY ROCKETRY ... VARIABLE STARS BINARY STARS BLACK HOLES PULSARS RED GIANTS COMETS ... DIFFERENT LANGUAGES Binary Stars What is a Binary Star? A binary star is defined as: a stellar system which is composed of two stars orbiting one another about their common center of mass. The two stars are held together by the force of their mutual gravity. The Evolution of Binary Star Systems For these stars, the presence of a close-by companion can have a profound influence on their evolution. Stars can exchange material, especially during the stages when one of them swells up into a giant or supergiant, or has a strong wind. When this happens and the companion stars are sufficiently close, material can flow from one star to another, decreasing the mass of the one and increasing the mass of the other. Such mass transfer can be especially dramatic when the recipient is a stellar remnant such as a white dwarf or neutron star. Visual Binary Stars A visual binary is defined as "A binary star in which two components are telescopically resolved."

65. Eclipsing Binary Stars (Article) INTRODUCTION Eclipsing binary stars are just one several types of variable stars. These stars appear as a single point of light to an observer, but based on its brightness http://www.physics.sfasu.edu/astro/ebstar/ebstar.html

ECLIPSING BINARY STARS A Simple Model for Computing Light Curves BASIC Subroutine Dan Bruton astro@sfasu.edu INTRODUCTION Eclipsing binary stars are just one several types of variable stars. These stars appear as a single point of light to an observer, but based on its brightness variation and spectroscopic observations we can say for certain that the single point of light is actually two stars in close orbit around one another. The variations in light intensity from eclipsing binary stars is caused by one star passing in front of the other relative to an observer. If we assume that the stars are spherical and that they have circular orbits, then we can easily approximate how the light varies as a function of time for eclipsing binary stars. These calculations can be performed in a relatively short computer program. THE ORBIT AND STAR PARAMETERS A brightness versus time plot for a variable star is know as light curve . For close binary systems, time is usually expressed as phase , for which one unit of time is the orbital period. Measured light curves for periodic variable stars are usually "folded", which means that successive cycles are plotted atop one another. An example of an experimentally measured light curve is given in Figure 1. Note that the vertical axis of the graph is labeled "magnitude" which is a logarithmic scale of brightness.

66. Binary Stars 1998 Aug 07 BINARY STARS In 1650 the Italian Jesuit Giovanni Riccioli observed that Mizar, one of two stars in the handle of Ursa Major long used as a test of visual acuity, itself had a very http://www.physics.uq.edu.au/people/ross/phys2080/binary/binaries.htm

BINARY STARS In 1650 the Italian Jesuit Giovanni Riccioli observed that Mizar, one of two stars in the handle of Ursa Major long used as a test of visual acuity, itself had a very close companion. The odds of two stars of similar brightness appearing so close together is too small not to suspect that the stars are actually physically close together, not like the chance grouping of Mizar and the fainter more distant of the pair Alcor. In the following years many such double stars were discovered and by 1804 William Herschel discovered that the fainter component of Castor (Castor B) had moved relative to the brighter component (Castor A), the first proof that gravity worked outside the solar system and the stars were gravitationally bound, visual binary stars In 1889 Pickering found that the spectral lines of the brighter component of Mizar (Mizar A) were usually double and the spacing varied with a regular 104 day period, the first spectroscopic binary to be discovered. Immediately after the discovery of the spectroscopic binary Mizar, Algol the demon star , beta Persei, was discovered to be a spectroscopic binary introducing the most important class of binary stars the eclipsing binary.

67. Binary Stars - Page 1 - Music - New York - Village Voice At 1 p.m. on April 16, over 2,000 New York public high school kids had an experience parallel to David Byrne's upon his initial exposure to Brazilian music. They came to hear http://www.villagevoice.com/2004-04-20/music/binary-stars/1/

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