A star system or stellar system is a small number of stars which orbit each other,[1] bound by gravitational attraction. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth Gravitation is a natural Phenomenon by which objects with Mass attract one another 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 clusters are groups of Stars which are gravitationally bound A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter 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]
Binary star systems
A stellar system of two stars is known as a binary star, binary star system or physical double star. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. Double Star is a Science fiction Novel by Robert A Heinlein, first serialized in Astounding Science Fiction 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. The tidal force is a secondary effect of the Force of Gravity and is responsible for the Tides It arises because the gravitational acceleration experienced Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object In Mathematics, an ellipse (from the Greek ἔλλειψις literally absence) is a Conic section, the locus of points in a In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star See Two-body problem. In Classical mechanics, the two-body problem is to determine the motion of two point particles that interact only with each other
Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole. Sirius is the brightest star in the night sky with a visual Apparent magnitude of &minus1 This article is about the star Procyon is also the mammalian genus to which raccoons belong Cygnus X-1 (abbreviated Cyg X-1) in the Constellation Cygnus. A black hole is a theoretical region of space in which the Gravitational field is so powerful that nothing not even Electromagnetic radiation (e
Multiple star systems
Multiple star systems or physical multiple stars are systems of more than two stars. A multiple star consists of three or more Stars which appear from the Earth to be close to one another in the sky 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. The dynamical system concept is a mathematical Formalization for any fixed "rule" which describes the Time dependence of a point's position The n -body problem is the problem of finding given the initial positions masses and velocities of n bodies their subsequent motions as determined by In Mathematics, chaos theory describes the behavior of certain dynamical systems – that is systems whose state evolves with time – that may exhibit dynamics that 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. In Astronomy, Kepler's Laws of Planetary Motion are three mathematical laws that describe the motion of Planets in the Solar System. In physics the term dynamics customarily refers to the time evolution of physical processes A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth Star clusters are groups of Stars which are gravitationally bound A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter
Observation
Most multiple star systems known are triple; for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity. HD 188753 is a Triple star system approximately 149 Light-years away in the Constellation of Cygnus (the Swan) [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. Selection bias is a distortion of evidence or data that arises from the way that the data are collected [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. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. Systems with higher multiplicities are also generally hierarchical. [7] 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. Castor (α Gem / α Geminorum / Alpha Geminorum is the second brightest star in the Constellation Gemini and one of the brightest stars in the [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. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star [11]
Examples
Binary
- Sirius, a binary consisting of a main-sequence type A star and a white dwarf. Sirius is the brightest star in the night sky with a visual Apparent magnitude of &minus1 A binary star is a Star system consisting of two Stars orbiting around their Center of mass. The main sequence is the name for a continuous and distinctive band of stars that appear on a plot of stellar color versus brightness A white dwarf, also called a degenerate dwarf, is a small Star composed mostly of Electron-degenerate matter.
- Epsilon Aurigae, an eclipsing binary. Epsilon Aurigae (ε Aur / ε Aurigae is a star in the Constellation Auriga. A binary star is a Star system consisting of two Stars orbiting around their Center of mass.
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. Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris commonly North(ern Star or Pole Star, and sometimes Lodestar The Hubble Space Telescope ( HST; also known colloquially as "the Hubble" or just "Hubble" is a space telescope that was carried into
- 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. Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation In Astronomy, a G V star is a Main-sequence Star of spectral type G and luminosity class V Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation Alpha Centauri (α Centauri / α Cen also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest Star in the southern Constellation According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool Star, of the Main sequence, either late K Proxima Centauri ( Latin la ''proximus proxima proximum'' meaning 'next to' or 'nearest to' is a Red dwarf Star approximately 4 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. A binary star is a Star system consisting of two Stars orbiting around their Center of mass. In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the 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. HD 188753 is a Triple star system approximately 149 Light-years away in the Constellation of Cygnus (the Swan) A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Cygnus (ˈsɪgnəs Swan, Κύκνος) is a northern Constellation. The system is composed of HD 188753A, a yellow dwarf; HD 188753B, an orange dwarf; and HD 188753C, a red dwarf. In Astronomy, a G V star is a Main-sequence Star of spectral type G and luminosity class V A K V star is a Main sequence ( Hydrogen -burning Star of spectral type K and luminosity class V According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool Star, of the Main sequence, either late K B and C orbit each other every 156 days, and, as a group, orbit A every 25. 7 years.
Quadruple
- 4 Centauri[13]
- Mizar is often said to have been the first binary star discovered when it was observed in 1650 by Giovanni Battista Riccioli[14], p. 4 Centauri is a Star in the Constellation Centaurus. It is a blue-white B-type Subgiant with an Apparent magnitude of This is an article about the star for other uses please see Mizar (disambiguation Mizar (ζ UMa / ζ Ursae Majoris is a Star in A binary star is a Star system consisting of two Stars orbiting around their Center of mass. Giovanni Battista Riccioli ( April 17 1598 – June 25 1671) was an Italian Astronomer. 1; ,[15] but it was probably observed earlier, by Benedetto Castelli and Galileo. Benedetto Castelli, born Antonio Castelli (1578 &ndash April 9 1643) was an Italian mathematician Galileo Galilei (15 February 1564 &ndash 8 January 1642 was a Tuscan ( Italian) Physicist, Mathematician, Astronomer, and Philosopher Later, spectroscopy of its components Mizar A and B revealed that they were both binary stars themselves. Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ [16]
- HD 98800
Quintuple
Sextuple
See also
References
- ^ "Star system" in Modern Dictionary of Astronomy and Space Technology. HD 98800, also cataloged as TV Crateris (TV Crt is a quadruple star system approximately 150 Light-years away in the Constellation of Nu Scorpii (ν Sco / ν Scorpii is a Star system in the Constellation Scorpius. Castor (α Gem / α Geminorum / Alpha Geminorum is the second brightest star in the Constellation Gemini and one of the brightest stars in the The Solar System consists of the Sun and those celestial objects bound to it by Gravity. A multiple star consists of three or more Stars which appear from the Earth to be close to one another in the sky An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 A. S. Bhatia, ed. New Delhi: Deep & Deep Publications, 2005. ISBN 81-7629-741-0
- ^ Astronomers discover a nearby star system just like our own Solar System, Joint Astronomy Centre, press release, July 8, 1998. Events 939 - The Major Occultation or Ghaybat el-Kubra of Muhammad al-Mahdi 1099 - First Crusade: 15000 Year 1998 ( MCMXCVIII) was a Common year starting on Thursday (link will display full 1998 Gregorian calendar) Accessed on line September 23, 2007. Events 1122 - Concordat of Worms. 1459 - Battle of Blore Heath, the first major battle of the English Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ Life unlikely in asteroid-ridden star system, Maggie McKee, NewScientist. com news service, July 7, 2004. Events 1456 - A retrial verdict acquits Joan of Arc of heresy 25 years after her death "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Accessed on line September 23, 2007. Events 1122 - Concordat of Worms. 1459 - Battle of Blore Heath, the first major battle of the English Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ 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.
- ^ Stars of Higher Multiplicity, David S. Evans, Quarterly Journal of the Royal Astronomical Society 9 (1968), 388–400.
- ^ Dynamics of multiple stars: observations, A. Tokovinin, in "Massive Stars in Interacting Binaries", August 16–20, 2004, Quebec (ASP Conf. Ser. , in print).
- ^ a b 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.
- ^ 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.
- ^ 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.
- ^ a b 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.
- ^ a b 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.
- ^ Are Proxima and α Centauri Gravitationally Bound?, Jeremy G. Wertheimer, Gregory Laughlin, Astronomical Journal 132, #5 (November 2006), pp. 1995–1997.
- ^ 4 Centauri, entry in the Multiple Star Catalog.
- ^ The Binary Stars, R. G. Aitken, New York: Semi-Centennial Publications of the University of California, 1918.
- ^ Vol. 1, part 1, p. 422, Almagestum Novum, Giovanni Battista Riccioli, Bononiae: Ex typographia haeredis Victorij Benatij, 1651.
- ^ A New View of Mizar, Leos Ondra, accessed on line May 26, 2007. Events 451 - The Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ Nu Scorpii, entry in the Multiple Star Catalog.
External links
Dictionary
star system
-noun
- (astronomy) A group of stars (and possibly smaller bodies such as planets or asteroids) that orbit one another.
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