FACTOID # 174: One in three Italian babies is born by caesarean section.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

FACTS & STATISTICS    Simple view

  1. Select countries to view: (hold down Control key and click to select several)

     

     

    Compare:

     

     
  1. Select fact or statistic: (* = graphable)

     

     

     

  2. (OPTIONAL) Compare to statistic: (both need to be graphable)

     

     

     

  3. View result as:

     

       
(OR) SEARCH ALL encyclopedia, stats & forums:   

Encyclopedia > Multiple star
Artist's impression of the orbits of HD 188753, a triple star system

A multiple star consists of three or more stars which appear from the Earth to be close to one another. This closeness may be merely apparent, in which case the multiple star is optical, or result from the stars being physically close and gravitationally bound to each other, in which case it is physical.[1][2][3] Physical multiple stars are multiple star systems. Multiple stars may be called triple if they have three stars, quadruple with four, and so on. A physical triple star is also called trinary, ternary or a triple star system. Image File history File links Size of this preview: 750 × 600 pixelsFull resolution (800 × 640 pixel, file size: 10 KB, MIME type: image/jpeg) Artists impression of the orbits of HD 188753, a hierarchical triple star system File historyClick on a date/time to view the file as it... Image File history File links Size of this preview: 750 × 600 pixelsFull resolution (800 × 640 pixel, file size: 10 KB, MIME type: image/jpeg) Artists impression of the orbits of HD 188753, a hierarchical triple star system File historyClick on a date/time to view the file as it... HD 188753 is a triple star system approximately 149 light-years away in the constellation Cygnus. ... A star system or stellar system is a small number of stars that orbit each other,[1] bound by gravitational attraction. ...


In a triple star system, each star orbits the center of mass of the system. Usually, two of the stars form a close binary star and the third is further away; this configuration is called hierarchical. Multiple star systems containing more than three stars are also usually hierarchical.[2], §2.4. Two bodies with a slight difference in mass orbiting around a common barycenter. ... In physics, the center of mass of a system of particles is a specific point at which, for many purposes, the systems mass behaves as if it were concentrated. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... A star system or stellar system is a small number of stars that orbit each other,[1] bound by gravitational attraction. ...

Contents

Examples

HD 98800 is a quadruple star system located in the TW Hydrae association
HD 98800 is a quadruple star system located in the TW Hydrae association
  • HR 3617 is a multiple star with three component stars, HR 3617A, HR 3617B, and HR 3617C. A and B form a physical binary star, while C is optical.
  • Alpha Centauri is a triple star composed of a main binary yellow dwarf pair (Alpha Centauri A and Alpha Centauri B), and an outlying red dwarf, Proxima Centauri. A and B are a physical binary star, with an eccentric orbit in which A and B can be as close as 11 AU or as far away as 36 AU. Proxima is much further away (~15,000 AU) from A and B than they are to each other. Although this distance is still small compared to other interstellar distances, it is debatable whether Proxima is gravitationally bound to A and B.[4]
  • HD 188753 is a physical triple star system located approximately 149 light years away from Earth in the constellation Cygnus. The system is composed of HD 188753A, a yellow dwarf; HD 188753B, an orange dwarf; and HD 188753C, a red dwarf. B and C orbit each other every 156 days, and, as a group, orbit A every 25.7 years.
  • Polaris, the north star, is a triple star system in which the closer companion star is extremely close to the main star—so close that it was only known from its gravitational tug on Polaris A until it was photographed by the Hubble Space Telescope in 2006.

Image File history File links Metadata Size of this preview: 750 × 600 pixelsFull resolution (3000 × 2400 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 750 × 600 pixelsFull resolution (3000 × 2400 pixel, file size: 1. ... artists impression of HD 98800 HD 98800 is a quadruple star system located in the TW Hydrae association. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... Large solar flare recorded by SOHO EIT304 instrument in the ultraviolet. ... Alpha Centauri A is a star of the star system Alpha Centauri. ... Alpha Centauri B (also Rigel Kentaurus B — the foot of the centaur in Arabic) is a star of the Alpha Centauri star system. ... For the type of star, see Red dwarf. ... Proxima Centauri (Latin proximus, -a, -um: meaning next to or nearest to)[4] is a red dwarf star that is likely a part of the Alpha Centauri star system and is the nearest star to the Sun at a distance of 4. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... The astronomical unit (AU or au or a. ... HD 188753 is a triple star system approximately 149 light-years away in the constellation Cygnus. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one year. ... This article is about Earth as a planet. ... Photo of the familiar constellation Orion. ... Cygnus (Latin for swan) is a northern constellation. ... Large solar flare recorded by SOHO EIT304 instrument in the ultraviolet. ... Orange dwarfs are main sequence stars of spectral type K. Categories: Star stubs | Orange dwarfs ... For the type of star, see Red dwarf. ... Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris), more commonly known as The North Star or simply North Star, is the brightest star in the constellation Ursa Minor. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ...

References

  1. ^ Hipparcos: Double and Multiple Stars, web page, accessed May 26, 2007.
  2. ^ a b MSC - a catalogue of physical multiple stars, A. A. Tokovinin, Astronomy and Astrophysics Supplement Series 124 (July 1997), pp. 75–84.
  3. ^ Binary and Multiple Stars, web page, accessed May 26, 2007.
  4. ^ Are Proxima and α Centauri Gravitationally Bound?, Jeremy G. Wertheimer, Gregory Laughlin, Astronomical Journal 132, #5 (November 2006), pp. 1995–1997.

is the 146th day of the year (147th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 146th day of the year (147th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ...

See also

For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... When two stars are so nearly in the same direction as seen from Earth that they appear to be a single star to the naked eye but may be separated by the use of telescopes, they are referred to as a double star. ... A star system or stellar system is a small number of stars that orbit each other,[1] bound by gravitational attraction. ...

External links

  • Triple star system, APOD
  • Alpha Centauri system, APOD
  • Alpa Centauri, APOD, 2002 April 25

  Results from FactBites:
 
Binary star (318 words)
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.
Since mass can be determined only from gravitational attraction, and the only stars (with the exception of the Sun) for which gravitational attraction can be determined are the binary stars, these stars are the one group from which the masses of stars may be determined.
In the case of a visual binary star, after the orbit has been determined and the stellar parallax of the system obtained, the combined mass of the two stars may be obtained by a direct application of the Keplerian harmonic law.
star. The Columbia Encyclopedia, Sixth Edition. 2001-05 (859 words)
The most luminous stars (excluding supernovas) are about a million times more powerful than the sun, while the least luminous are only one hundredth as powerful red giants, the largest stars, are hundreds of times greater in size than the sun; if one were placed at the sun’s position, it would engulf Mars.
Light received from a star consists of a spectrum of wavelengths; the hotter the star, the shorter the wavelength at which the light is most intense.
Many stars that appear as single points of light in even the most powerful telescopes are actually systems of two or more stars orbiting one another, bound together by their mutual gravitational attraction; the binary stars are most common among these multiple star systems.
  More results at FactBites »


 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments
Please enter the 5-letter protection code

Want to know more?
Search encyclopedia, statistics and forums:
 


Lesson Plans | Student Area | Student FAQ | Reviews | Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms.