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Information about Star System

This article is about stars in outer space. For the Hollywood star system, see star system (film).
For a system of planets, see planetary system


A star system or stellar system is a small number of stars which orbit each other,[1] bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems. Star system is occasionally also used to refer to a system of a single star together with a planetary system of orbiting smaller bodies.[2][3]

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The binary orbit of Procyon B around Procyon A.

Binary star systems

Main article: Binary star


A stellar system of two stars is known as a binary star, binary star system or physical double star. If there are no tidal effects, no perturbation from other forces, and no transfer of mass from one star to the other, such a system is stable, and both stars will trace out an elliptical orbit around the center of mass of the system indefinitely. See Two-body problem.

Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole.

Multiple star systems

Multiple star systems or physical multiple stars are systems of more than two stars. Multiple star systems are called triple, trinary or ternary if they contain three stars; quadruple or quaternary if they contain four stars; quintuple with five stars; sextuple with six stars; septuple with seven stars; and so on.

Dynamics

Theoretically, modelling a multiple star system is more difficult than modelling a binary star, as the dynamical system involved, the n-body problem, may exhibit chaotic behavior. Many configurations of small groups of stars are found to be unstable, as eventually one star will approach another closely and be accelerated so much that it will escape from the system.[4] This instability can be avoided if the system is what Evans[5] has called hierarchical. In a hierarchical system, the stars in the system can be divided into two smaller groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. In this case, the stars' motion will continue to approximate stable Keplerian orbits around the system's center of mass[6], unlike the more complex dynamics of the large number of stars in star clusters and galaxies.

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

Observation

Most multiple star systems known are triple; for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity.[7] For example, in the 1999 revision of Tokovinin's catalog[8] of physical multiple stars, 551 out of the 728 systems described are triple. However, because of selection effects, our knowledge of these statistics is very incomplete.[9], §2.

Because of the dynamical instabilities mentioned earlier, triple systems are generally hierarchical: they contain a close binary pair which has a more distant companion. Systems with higher multiplicities are also generally hierarchical.<ref name="tok1" /> Systems with up to six stars are known; for example, Castor (Alpha Geminorum), which consists of a binary pair in a distant orbit of two closer binary pairs.[10] Another system known with six stars is ADS 9731, which consists of a pair of two triple systems, each of which is a spectroscopic binary in orbit together with a single star.[11]

Examples

Binary

Triple

  • 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.
  • 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.[12]
  • HD 188753 is a 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.

Quadruple

Quintuple

Sextuple

  • Castor<ref name="castor" />
  • ADS 9731<ref name="ads9731" />

See also

References

1. ^ "Star system" in Modern Dictionary of Astronomy and Space Technology. A.S. Bhatia, ed. New Delhi: Deep & Deep Publications, 2005. ISBN 81-7629-741-0
2. ^ Astronomers discover a nearby star system just like our own Solar System, Joint Astronomy Centre, press release, July 8, 1998. Accessed on line September 23, 2007.
3. ^ Life unlikely in asteroid-ridden star system, Maggie McKee, NewScientist.com news service, July 7, 2004. Accessed on line September 23, 2007.
4. ^ Multiple Stellar Systems: Types and Stability, Peter J. T. Leonard, in Encyclopedia of Astronomy and Astrophysics, P. Murdin, ed., online edition at the Institute of Physics, orig. ed. published by Nature Publishing Group, 2001.
5. ^ Stars of Higher Multiplicity, David S. Evans, Quarterly Journal of the Royal Astronomical Society 9 (1968), 388–400.
6. ^ Dynamics of multiple stars: observations, A. Tokovinin, in "Massive Stars in Interacting Binaries", August 16–20, 2004, Quebec (ASP Conf. Ser., in print).
7. ^ Statistics of multiple stars: some clues to formation mechanisms, A. Tokovinin, in the proceedings of IAU Symposium 200, The Formation of Binary Stars, Potsdam, Germany, April 10–15, 2000. Bibcode 2001IAUS..200...84T.
8. ^ MSC—a catalogue of physical multiple stars, A. A. Tokovinin, Astronomy and Astrophysics Supplement Series 124 (1997), 75–84; online versions at VizieR and the Multiple Star Catalog.
9. ^ Statistics of multiple stars, A. Tokovinin, in The Environment and Evolution of Double and Multiple Stars, Proceedings of IAU Colloquium 191, held 3-7 February, 2002 in Merida, Yucatan, Mexico, edited by Christine Allen and Colin Scarfe, Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) 21 (August 2004), pp. 7–14.
10. ^ Castor A and Castor B resolved in a simultaneous Chandra and XMM-Newton observation, B. Stelzer and V. Burwitz, Astronomy and Astrophysics 402 (May 2003), pp. 719–728.
11. ^ ADS 9731: A new sextuple system, A. A. Tokovinin, N. I. Shatskii, and A. K. Magnitskii, Astronomy Letters, 24, #6 (November 1998), pp. 795–801.
12. ^ Are Proxima and α Centauri Gravitationally Bound?, Jeremy G. Wertheimer, Gregory Laughlin, Astronomical Journal 132, #5 (November 2006), pp. 1995–1997.
13. ^ 4 Centauri, entry in the Multiple Star Catalog.
14. ^ The Binary Stars, R. G. Aitken, New York: Semi-Centennial Publications of the University of California, 1918.
15. ^ Vol. 1, part 1, p. 422, Almagestum Novum, Giovanni Battista Riccioli, Bononiae: Ex typographia haeredis Victorij Benatij, 1651.
16. ^ A New View of Mizar, Leos Ondra, accessed on line May 26, 2007.
17. ^ Nu Scorpii, entry in the Multiple Star Catalog.

External links

The star system was the method of creating and promoting film stars in Classical Hollywood cinema. Studios would select promising young actors and create personas for them, often inventing new names and even new backgrounds.
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planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust.[1][2] The Sun together with its planetary system, which includes Earth, is known as the Solar System.
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STAR is an acronym for:

Organizations:
  • Society for Telescopy, Astronomy, and Radio, a non-profit astronomy club in New Jersey
  • Special Tasks and Rescue or Special Tactics and Response, synonyms for SWAT

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Gravitation is a natural phenomenon by which all objects with mass attract each other. In everyday life, gravitation is most familiar as the agency that endows objects with weight.
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Star clusters are groups of stars which are gravitationally bound. Two distinct types of star cluster can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars, while open clusters generally contain less than a few hundred members, and are
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A galaxy (from the Greek root γαλαξίας, meaning "milky", a reference to our own Milky Way) is a massive, gravitationally bound system consisting of stars, an interstellar medium of gas and dust, and dark matter.
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planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust.[1][2] The Sun together with its planetary system, which includes Earth, is known as the Solar System.
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binary star is a stellar system consisting of two stars orbiting around their center of mass. For each star, the other is its companion star. Recent research suggests that a large percentage of stars are part of systems with at least two stars.
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binary star is a stellar system consisting of two stars orbiting around their center of mass. For each star, the other is its companion star. Recent research suggests that a large percentage of stars are part of systems with at least two stars.
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double star is when two stars appear close to each other as seen from Earth.

There are two kinds of double star: visual binaries and optical binaries. Visual binaries are considered to be a true binary star system and lie close enough together in space to
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tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational field is not constant across a body's diameter.
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Mass is a fundamental concept in physics, roughly corresponding to the intuitive idea of "how much matter there is in an object". Mass is a central concept of classical mechanics and related subjects, and there are several definitions of mass within the framework of relativistic
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ellipse (from the Greek ἔλλειψις, literally absence) is the locus of points on a plane where the sum of the distances from any point on the curve to two fixed points is constant.
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ORBit is a CORBA compliant Object Request Broker (ORB). The current version is called ORBit2 and is compliant with CORBA version 2.4. It is developed under the GPL license and is used as middleware for the GNOME project.
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center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated. The center of mass is a function only of the positions and masses of the particles that comprise the system.
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two-body problem is to determine the motion of two point particles that interact only with each other. Common examples include a satellite orbiting a planet, a planet orbiting a star, two stars orbiting each other (a binary star), and a classical electron orbiting an atomic nucleus.
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Sirius (α CMa / α Canis Majoris / Alpha Canis Majoris) (IPA: /ˈsɪriəs/) is the brightest star in the night-time sky with a visual apparent magnitude of −1.47.
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This article is about the star. Procyon is also the mammalian genus to which raccoons belong.
Procyon (α CMi / α Canis Minoris / Alpha Canis Minoris) is the brightest star in the constellation Canis Minor and the seventh brightest star in
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For the song(s) by Rush, see .
Cygnus X-1 (often abbreviated to Cyg X-1) is an X-ray source in the constellation Cygnus, and considered to be a black hole.
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black hole is a region of space in which the gravitational field is so powerful that nothing can escape after having fallen past the event horizon. The name comes from the fact that even electromagnetic radiation (e.g. light) is unable to escape, rendering the interior invisible.
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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
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dynamical system concept is a mathematical formalization for any fixed "rule" which describes the time dependence of a point's position in its ambient space. Examples include the mathematical models that describe the swinging of a clock pendulum, the flow of water in a pipe, and
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n-body problem is the problem of finding, given the initial positions, masses, and velocities of n bodies, their subsequent motions as determined by classical mechanics, i.e., Newton's laws of motion and Newton's law of gravity.
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chaos theory describes the behavior of certain nonlinear dynamical systems that under specific conditions exhibit dynamics that are sensitive to initial conditions (popularly referred to as the butterfly effect).
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center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated. The center of mass is a function only of the positions and masses of the particles that comprise the system.
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Kepler's laws of planetary motion are three mathematical laws that describe the motion of planets in the Solar System. German mathematician and astronomer Johannes Kepler (1571–1630) discovered them.
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In physics, dynamics is the branch of classical mechanics that is concerned with the effects of forces on the motion of objects. The former distinguishes it from kinematics and the latter distinguishes it from statics.
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STARS can mean:
  • Shock Trauma Air Rescue Society
  • Special Tactics And Rescue Service, a fictional task force that appears in Capcom's Resident Evil video game franchise.

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Star clusters are groups of stars which are gravitationally bound. Two distinct types of star cluster can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars, while open clusters generally contain less than a few hundred members, and are
..... Click the link for more information.
A galaxy (from the Greek root γαλαξίας, meaning "milky", a reference to our own Milky Way) is a massive, gravitationally bound system consisting of stars, an interstellar medium of gas and dust, and dark matter.
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