Презентация научной работы по астрономии на английском языке.
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Moskalev ivan 11 form EXOPLANETSСлайд 2
Contents Introduction History of discoveries Some methods of exoplanets` detection Nomenclature Habitable zone The closet exoplanet to Earth Exoplanets` meaning in modern world Literature used
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introduction The first attempts to find planets outside the solar system have been associated with observations of the position of nearby stars. In the sixteenth century the Italian philosopher Giordano Bruno put forward the view that the fixed stars are similar to the Sun and are likewise accompanied by planets.
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History of discoveries An exoplanet , or extrasolar planet , is a planet outside the Solar System. More than a thousand such planets have been discovered. As of 4 November 2013, the Kepler mission space telescope has detected 3,568 candidate planets For centuries philosophers and scientists supposed that extrasolar planets existed, but there was no way of detecting them or of knowing their frequency or how similar they might be to the planets of the Solar System. First extrasolar planet was found by C anadians B. Campbell, G. Walker and S. Young in 1988 in orange subgiant Gamma Cephei A, but only confirmed in 2002.
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Some Methods of exoplanets` detection Radial velocity or Doppler method As a planet orbits a star, the star also moves in its own small orbit around the system's center of mass. Variations in the star's radial velocity—that is, the speed with which it moves towards or away from Earth—can be detected from displacements in the star's spectral lines due to the Doppler effect. Extremely small radial-velocity variations can be observed, of 1 m/s or even somewhat less. This has been by far the most productive method of discovering exoplanets. It has the advantage of being applicable to stars with a wide range of characteristics. One of its disadvantages is that it cannot determine a planet's true mass, but can only set a lower limit on that mass. Transit method If a planet crosses (or transits) in front of its parent star's disk, then the observed brightness of the star drops by a small amount. The amount by which the star dims depends on its size and on the size of the planet, among other factors. The transit method reveals the radius of a planet, and it has the benefit that it sometimes allows a planet's atmosphere to be investigated through spectroscopy.
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Nomenclature Discovered extrasolar planets currently assigned name consisting of the name of the star around which the planet turns , and more lowercase letters of the alphabet , starting with «b». Next planet is assigned the letter «c», then «d» and so on in alphabetical order. The letter «a» in the title is not used , as its name would imply an actual star itself. The planets are named in order of their discovery , and not as the distance from the star treatment. That is , the planet "c" may be closer to the star than the planet «b».
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Habitable zone Habitable zone - in astronomy conditional region in space defined on the basis of the conditions on the surface of the planets are in it will be close to the conditions on Earth surface and to ensure the existence of liquid water . Accordingly, these planets and moons will be favorable for the emergence of life, similar to Earth's. Data from the Habitable Exoplanets Catalog suggests that, of the 859 exoplanets which have been confirmed as of 3 January 2013, nine potentially habitable planets have been found, and the same source predicts that there may be 30 habitable extrasolar moons around confirmed planets.
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The closest exoplanet to earth Alpha Centauri Bb is a possible extrasolar planet orbiting the star Alpha Centauri B, located 4.37 light-years from Earth in the southern constellation of Centaurus. If verified, it would be the closest extrasolar planet to Earth ever discovered, and the lowest-minimum-mass planet detected so far around a solar-type star. Its existence was announced in October 2012 by a team of European observers.
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Exoplanets` meaning in modern world Discovery of exoplanets has allowed astronomers to conclude that planetary systems - a common phenomenon in space. There is still no generally accepted theory of planet formation, but now, when the opportunity to take statistics, the situation has changed for the better. The discovery of exoplanets has intensified interest in the search for extraterrestrial life, particularly for those that orbit in the host star's habitable zone where it is possible for liquid water (and therefore life) to exist on the surface. The search for extrasolar planets prompts the study of planetary habitability, which considers a wide range of factors in determining the suitability of an extrasolar planet for hosting life.
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Literature used http:// en.wikipedia.org/wiki/Exoplanets http:// en.wikipedia.org/wiki/Doppler_spectroscopy http:// en.wikipedia.org/wiki/Habitable_zone http :// en.wikipedia.org/wiki/Alpha_Centauri_Bb
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