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Topic: Binary star


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  Binary star - Wikipedia, the free encyclopedia
Binary stars are also interesting as it is possible for the companions to exchange mass, bringing their evolution to stages that single stars cannot attain.
Binary stars may be found with any conceivable separation, from pairs orbiting so closely that they are practically in contact with each other, to pairs so distantly separated that their connection is indicated only by their common proper motion through space.
In the case of a visual binary star, after the orbit has been determined and the stellar parallax of the system determined, the combined mass of the two stars may be obtained by a direct application of the Keplerian harmonic law.
en.wikipedia.org /wiki/Binary_star   (1798 words)

  
 Eclipsing binary - Wikipedia, the free encyclopedia
An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses.
In the case where the binary is also a spectroscopic binary and the parallax of the system is known, the binary is quite valuable for stellar analysis.
The light curve of an eclipsing binary is characterized by periods of practically constant light, with periodic drops in intensity.
en.wikipedia.org /wiki/Eclipsing_binary   (246 words)

  
 AllRefer.com - binary star (Astronomy, General) - Encyclopedia
The more massive star (A) of a binary is called the primary, and the less massive (B) is called the secondary; e.g., Sirius A and Sirius B are the primary and secondary components of the Sirius system.
Binary stars are thus important indicators from which the masses of all similar stars can be deduced.
Although most binary stars have distance between them, the components of W Ursae Majoris binaries are actually in contact with each other, their mutual gravity distorting their shapes into teardrops.
reference.allrefer.com /encyclopedia/B/binaryst.html   (566 words)

  
 binary star
Physical double stars are binaries, whereas optical doubles are not.
In a spectroscopic binary, the apparent separation is so small that the presence of two stars can only be deduced from regular changes in the Doppler shift of the stars’ spectral lines.
In a close binary the separation is comparable to the diameter of the stars.
www.daviddarling.info /encyclopedia/B/binarystar.html   (234 words)

  
 binary star. The Columbia Encyclopedia, Sixth Edition. 2001-05
or binary system, pair of stars that are held together by their mutual gravitational attraction and revolve about their common center of mass.
True binary stars are distinct from optical doubles—pairs of stars that lie nearly along the same line of sight from the earth but are not physically associated.
A visual binary is a pair of stars that can be seen by direct telescopic observation to be a distinct pair with shared motion.
www.bartleby.com /65/bi/binaryst.html   (497 words)

  
 Visual Binaries
Some binary systems are sufficiently close to Earth and the stars are well enough separated that we can see the two stars individually in a telescope and track their motion over a period of time.
In this case the plot is of the orbit of one star relative to the other and the year of the observation is given at the corresponding point on the orbit.
In reality, binary star systems are governed by Kepler's laws, as modified by Newton to account for the effect of the center of mass.
csep10.phys.utk.edu /astr162/lect/binaries/visual.html   (462 words)

  
 Binary Stars   (Site not responding. Last check: 2007-10-21)
The binary nature of the system is deduced from the periodic doppler shifts of the wavelengths of lines seen in the spectrum, as the stars move through their orbits around the center of mass.
Eclipsing binaries are systems in which the orbital plane is oriented exactly edgewise to the plane of the sky so that the one star passes directly in front of the other, blocking out its light during the eclipse.
We estimate that roughly half of all stars in the sky are indeed members of binaries.
astrosun2.astro.cornell.edu /academics/courses/astro201/binstar.htm   (307 words)

  
 Binary Star Simulation   (Site not responding. Last check: 2007-10-21)
A simplified derivation of the magnitude of the reflex motion of the star due to an orbiting planet can be found here.
The observed velocities of the two stars, and the Doppler shifted spectral lines (as seen against the combined continuum from the two stars) are also shown in the upper rightbox.
The spectral lines associated with each star are indicated and the unshifted line positions are also marked.
instruct1.cit.cornell.edu /courses/astro101/java/binary/binary.htm   (377 words)

  
 binary star concept from the Astronomy knowledge base   (Site not responding. Last check: 2007-10-21)
Astrometric binaries are those whose dual nature can be deduced from their variable proper motion; spectroscopic binaries, those whose dual nature can be deduced from their variable radial velocity.
Spectroscopic binaries are typically of spectral type B, with almost circular orbits (whereas long-period M-type binaries have highly eccentric orbits).
Like other flare stars, it is a member of a binary system in which both components are of nearly equal brightness.
www.site.uottawa.ca:4321 /astronomy/binarystar.html   (853 words)

  
 Eclipsing Binary Stars   (Site not responding. Last check: 2007-10-21)
The majority of these stars are found in binary systems which are systems of two stars in orbit around a common center of mass.
Stars that are far enough apart to be distinguished from each other are known as visual binaries.
Other binaries are too close and far away to be seen separately but can distinguished using the doppler shift of their spectra.
members.cox.net /astro7/binstar.html   (728 words)

  
 Eclipsing Binary Stars (Article)
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.
The star masses and luminosities can be expressed in arbitrary units and the star radii will be expressed in terms of a fraction of the orbit radius of the binary star orbit.
www.physics.sfasu.edu /astro/ebstar/ebstar.html   (1064 words)

  
 GAT: binary star - Wikibooks, collection of open-content textbooks
A binary star system consists of two stars that are orbiting their common center of mass.
The distances between stars in binary systems vary widely; sometimes they seem almost to touch, and other times their association may not be readily apparent.
The gravitational interaction of binary stars allows astronomers to calculate the masses of these stars, something which is not possible with singular stars.
en.wikibooks.org /wiki/GAT:_binary_star   (198 words)

  
 Binary and Multiple Stars   (Site not responding. Last check: 2007-10-21)
Binary and multiple stars are common in the universe.
The component stars in multiple systems orbit each other, and move around their center of mass, because of their mutual gravitational interaction, an effect which can be noted by observation of changes of their relative positions and radial velocities, and are all at about the same distance from us.
These can be distinguished from physical binaries by observation, as the "component" stars, at their different distances, move independent from each other and show different and mutually uneffected velocities (radial velocities and proper motions).
www.seds.org /messier/bina.html   (437 words)

  
 Binary Research Institute   (Site not responding. Last check: 2007-10-21)
In examining the phenomenon of precession of the equinox (which was the original impetus for the development of lunisolar precession theory) we have found that a binary orbit motion of our sun and solar system is a simpler way to reproduce the same observable without any of the problems associated with current precession theory.
The stars can be of the same or differing sizes and orbits can be as short as a few days or as long as thousands of years.
While there is no obvious visible companion star to our Sun, there could be a dark binary, such as a brown dwarf or possibly a relatively small fl hole, either of which might be very difficult to detect, without accurate and lengthy analysis.
www.binaryresearchinstitute.org /introduction/binary.shtml   (335 words)

  
 HR Diagram
There are also a handful of stars which are red and very bright (called red supergiants) and a few stars that are hot, but very faint (called white dwarfs).
Stars begin their life on the main sequence, but then evolve off into red giant phase and supergiant phase before dying as white dwarfs or some more violent endpoint.
However, due to the high densities in the core of a star, all these objects are trapped in the center and, thus, we can not `see' what goes on inside a star.
zebu.uoregon.edu /~js/ast122/lectures/lec11.html   (1091 words)

  
 SPACE.com -- Planet Found in Tight Binary Star System
The planet orbits 2 AU from the larger star in the Gamma Cephei system, while the secondary star is a mere 28-30 AU distant.
In previous discoveries of planets orbiting stars in binary systems, the stars were a hundred times farther apart than those of Gamma Cephei, Cochran said.
Researchers monitor minor shifts in the light's wavelengths that indicate a star is wobbling due to the tug of an orbiting planet.
www.space.com /scienceastronomy/binary_planet_021009.html   (588 words)

  
 X-ray Binary Stars - Introduction
Binary star systems contain two stars that orbit around their common center of mass.
X-ray binaries are made up of a normal star and a collapsed star (a white dwarf, neutron star, or fl hole).
These pairs of stars produce X-rays if the stars are close enough together that material is pulled off the normal star by the gravity of the dense, collapsed star.
imagine.gsfc.nasa.gov /docs/science/know_l1/binary_stars.html   (251 words)

  
 binary star
binary star or binary system,pair of stars that are held together by their mutual gravitational attraction and revolve about their common center of mass.
eclipsing binary star - eclipsing binary star: see binary star; variable star.
variable star - variable star, star that varies, either periodically or irregularly, in the intensity of the light...
www.factmonster.com /ce6/sci/A0807587.html   (510 words)

  
 binary star
It is the limit (distance) from either star, where the star's atmosphere has extended/swolen to where the gravitational pull of the companion has as much effect on the gasses as does the expanding star.
Contact binaries are usually described as a situation where (a) the orbits are very close, therefore short period orbits and (b) where both stars have extended atmospheres beyond their Roche Lobes (limits), and material from both stars is intermixed.
It is the "merger" (collision?) of neutron stars, and maybe occassional fl holes, that are thought to be the source of the huge energy release of gamma ray bursts.
www.physicsforums.com /showthread.php?t=2893   (2657 words)

  
 Open Directory - Science: Astronomy: Stars: Binary Stars   (Site not responding. Last check: 2007-10-21)
Astronomical League Double Star Club - The purpose of the Double Star Club is to introduce observers to 100 of the finest double and multiple stars in the heavens.
The Double Star Library - The Double Star Library hopes to be a means by which various types of binary and multiple star information can be easily disseminated among binary star astronomers in IAU Commission 26 and related commissions.
The Formation of Binary Stars - Recent observational investigations of the frequency of occurrence of pre-main-sequence binary stars have reinforced earlier suspicions that binary formation is the primary branch of the star-formation process
dmoz.org /Science/Astronomy/Stars/Binary_Stars   (425 words)

  
 Eclipsing Binary Simiulation   (Site not responding. Last check: 2007-10-21)
Orbiting stars which are separated by a small distance may pass in front of one another.
It is not possible for astronomers to see the individual stars, but there will be a change in the total light coming from the two stars when they "eclipse" one another.
Note that when the F-star is in front of the A-star light from the system is reduced more than when the F-star is behind the A-star.
instruct1.cit.cornell.edu /courses/astro101/java/eclipse/eclipse.htm   (183 words)

  
 APOD: February 19, 1997 - Mizar Binary Star   (Site not responding. Last check: 2007-10-21)
binary star system, each star of the pair follows an elliptical orbital path.
Mizar is the middle star in the handle of the Big Dipper and at a distance of 88 light years, was the first binary star system
But, the companions are too close to be directly observed as separate stars, even by the largest telescopes.
antwrp.gsfc.nasa.gov /apod/ap970219.html   (214 words)

  
 Binary Star Software   (Site not responding. Last check: 2007-10-21)
Your first job is to use the Mac Chart tool to discover which of the stars in the field is actually the eclipsing binary - it's a puzzling problem.
Your next job is to use the Mac.Period tool to measure the orbital period of the eclipsing binary to 6-digits accuracy.
A robotic telescope measures the times of eclipse of a group of eclipsing binary stars.
www.uark.edu /misc/clacy/BinaryStars/software.htm   (328 words)

  
 ESA Science & Technology: The massive binary companion star to the progenitor of supernova 1993J
The massive star that underwent a collapse of its core to produce supernova (SN)1993J was subsequently identified as a non-variable red supergiant star in images of the galaxy M81 taken before explosion.
It showed an excess in ultraviolet and B-band colours, suggesting either the presence of a hot, massive companion star or that it was embedded in an unresolved young stellar association.
At the position of the fading supernova we detect the unambiguous signature of a massive star: the binary companion to the progenitor.
sci.esa.int /science-e/www/object/index.cfm?fobjectid=37390   (207 words)

  
 eBay - binary star, CDs, Records items on eBay.com   (Site not responding. Last check: 2007-10-21)
Binary Star #4 - Legacy; The Janus Equation
Eclipsing Binary Stars by E.F. Milone, Josef Kallrat...
Eclipsing Binary Stars - Kallrath, Josef/ Milone, *NEW
search-desc.ebay.com /search/search.dll?query=binary+star&newu=1&krd=1   (430 words)

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