An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 59 Search : planet
intramercurial planet
  سیاره‌ی ِ فروتیری   
sayyâre-ye forutiri

Fr.: planète intramercurienne   

A hypothetical planet, named Vulcan, that once was believed to exist between the Sun and Mercury.

intra-; → Mercury; → planet.

Jovian planet
  سیاره‌ی ِ هرمزی   
sayyâre-ye Hormozi

Fr.: planète jovienne   

A planet that does not have a well-defined → solid  → crust, such as any of the four Solar System outer, gaseous planets: → Jupiter, → Saturn, → Uranus, and → Neptune.

Jovian; → planet.

major planet
  سیاره‌ی ِ مهین   
sayyâre-ye mehin

Fr.: planète majeure   

A name used to describe any planet that is considerably larger and more massive than the Earth, and contains large quantities of hydrogen and helium. Jupiter and Neptune are examples of major planets.

major; → planète.

minor planet
  سیارک   
sayyârak (#)

Fr.: petite planète   

An obsolete name used to describe an → asteroid.

minor; → planet.

multiplanet system
  راژمان ِ بس-سیاره‌ای   
râžmân-e bas-sayâre-yi

Fr.: système multi-planète   

A stellar system with more than one orbiting planet.

multi-; → planet; → system.

ocean planet
  سیاره‌ی ِ اقیانوسی   
sayyâre-ye oqyânusi

Fr.: planète océan   

A hypothetical → exoplanet covered by a water envelope. The presence of such a planet stems from the implicit assumption of → Habitable Zone temperatures and a liquid water surface.

ocean; → planet.

outer planet
  سیاره‌یِ بیرونی   
seyyâre-ye biruni (#)

Fr.: planète extérieure   

A planet that revolves around the Sun beyond the → asteroid belt, namely → Jupiter, → Saturn, → Uranus, and → Neptune.

out; → planet.

planet
  سیاره   
sayyâré (#)

Fr.: planète   

1) A celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit. → dwarf planet.
2) → extrasolar planet.

From O.E., from O.Fr. planete (Fr. planète), from L.L. planeta (plural form planetae), from Gk. planetes (single form) "wandering," from (asteres) planetai "wandering (stars)," from planasthai "to wander," of unknown origin.

Sayyâré, from Ar. saiyârat "walker, traveller."

Planet Nine
  سیاره‌ی ِ نه   
sayyâre-ye noh

Fr.: Planète Neuf   

A hypothetical large planet in the far outer → solar system the gravitational effects of which would explain the unexpected orbital configuration of a group of → trans-Neptunian objects (TNOs). Trujillo & Sheppard (2014) noticed a clustering of the → argument of perihelion of bodies lying beyond ~150 → astronomical unit (AU), and attributed this to a hypothetical super-Earth body lying at several hundred AUs. Batygin & Brown (2016) showed numerically and analytically how the apsidal and nodal clustering of the distant TNOs arises as a result of resonant and secular dynamical effects from a distant perturber. They identified a range of semimajor axes (400-1500 AU) and eccentricities (0.5-0.8) for which a distant planet can explain the → orbital elements of the distant TNOs. The predicted planet would have a mass of 10 Earths (approximately 5,000 times the mass of → Pluto), a diameter of four times Earth and a highly elliptical orbit with an → orbital period of approximately 15,000 years.

planet; → nine.

planetarium
  ۱) آسمان‌نما؛ ۲) آسمان‌خانه   
1) âsmânnemâ; 2) âsmânxâné (#)

Fr.: planétarium   

1) A device that produces a representation of the heavens by the use of a number of moving projectors.
2) The building or room in which such a device is housed.

From → planet + -arium "a place for."

&ACIRC;smânnemâ, literally "sky displayer," from âsmân "sky" (Mid.Pers. âsmân "sky, heaven;" O.Pers. asman- "heaven;" Av. asman- "stone, sling-stone; heaven;" cf. Skt. áśman- "stone, rock, thunderbolt;" Gk. akmon "heaven, meteor, anvil;" Akmon was the father of Ouranos (Uranus), god of sky; Lith. akmuo "stone;" Rus. kamen; PIE base *akmon- "stone, sky." The link between the "stone" and "sky" concepts indicates that the sky had once been conceived as a stone vault by prehistoric Indo-Europeans) + nemâ "displayer," from nemudan "to show" (Mid.Pers. nimūdan, nimây- "to show," from O.Pers./Av. ni- "down; into" (Skt. ni "down," nitaram "downward," Gk. neiothen "from below," cf. E. nether, O.E. niþera, neoþera "down, downward, below, beneath," from P.Gmc. *nitheraz, Du. neder, Ger. nieder; PIE *ni- "down, below") + māy- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure").
&ACIRC;smânxâné, literally "sky house," from âsmân + xâné "house" (Mid.Pers. xânak, xân, xôn; cf. L. cunae "cradle;" Gk. kome "village;" Pers. Aftari dialect kiye "house, home;" PIE base *kei- "bed; to lie, to settle; beloved" (other cognates: P.Gmc. *khaim-; O.E. ham "dwelling, house, village;" E. home; Ger. Heim; L. civis "townsman;" Fr. cité; E. city; Skt. śiva- "auspicious, dear").

planetary
  سیاره‌ای   
sayyâre-yi (#)

Fr.: planétaire   

Of, pertaining to, or resembling a planet or planets.

planet; → -ary.

planetary aberration
  بیراهش ِ سیاره‌ای   
birâheš-e sayyâreyi

Fr.: aberration planétaire   

The difference between the true position of a planet and its apparent position, due to the time required for light to travel the distance from the planet to Earth. Correction for planetary aberration is necessary in determining orbits.

planetary; → aberration.

planetary nebula
  میغ ِ سیاره‌ای   
miq-e sayyâreyi

Fr.: nébuleuse planétaire   

A hot envelope of gas ejected from a central evolved star before becoming a → white dwarf. At the end of the → asymptotic giant phase the pulsating → red giant star is surrounded by an extended shell formed by the material ejected from it. As the evolved star contracts, its → effective temperature rises considerably. When it reaches about 30,000 K, the radiated photons become energetic enough to ionize the atoms in the nebula. The nebula becomes then visible in the optical. It shines essentially in a few → emission lines, produced by cascades during recombination or by collisional excitation with electrons. The central stars of planetary nebulae, → CSPNe, are typically 0.6 to 0.8 solar masses. They have → main sequence masses in the range 1 to 8 solar masses, with an average mass of 2.2 solar masses for a standard → initial mass function. Thus a total of about 1.6 solar masses is in average lost during the → AGB and planetary nebula phases. The life-time of planetary nebulae is relatively short. A typical planetary nebula lasts only a few 10,000 years.

planetary; → nebula. The name comes from the fact that these objects appear as planetary disks in a low-resolution telescope. The first planetary nebula, designated NGC 7009 or the → Saturn Nebula, was discovered in 1782 by the German-born English astronomer William Herschel (1738-1822), who described it as "planetary nebula."

planetary physics
  فیزیک ِ سیارگان   
fizik-e sayyâregân (#)

Fr.: physique des planètes   

The study of the structure, composition, as well as physical and chemical properties of the planets of the solar system, including their atmospheres and their immediate cosmic environment.

planetary; → physics.

planetary precession
  پیشایان ِ سیاره‌ای   
pišâyân-e sayyâre-yi

Fr.: précession planétaire   

The motion of the → ecliptic plane caused by the gravitational influence of the other planets, mainly → Jupiter. The observational effect of planetary precession is similar to that of the → lunisolar precession. But planetary precession causes the → equinoxes to move along the ecliptic in the opposition direction (eastward) from that of luni-solar precession (westward) and at a much slower rate: 0''.12 per year. Same as → precession of ecliptic.

planetary; → precession.

planetary ring system
  راژمان ِ حلقه‌های ِ سیاره‌ای   
râžmân-e halqehâ-ye sayyâre-yi

Fr.: système d'anneaux planétaires   

Interplanetary dust and other small particles organized into thin, flat rings encircling a planet. The most spectacular planetary rings known are those around → Saturn, but the other three → giant planets of the solar system (→ Jupiter, → Uranus, and → Neptune) have their own ring systems.

planetary; → ring; → system.

planetary science
  سیاره‌شناسی   
sayyârešenâsi (#)

Fr.: planétologie   

The branch of astronomy that deals with the science of planets, or planetary systems, and the solar system.

planetary; → science.

planetary system
  راژمان ِ سیاره‌ای   
râžmân-e sayyâreyi

Fr.: système planétaire   

A system composed of a star and all the celestial bodies bound to it by gravity, especially planets and their natural satellites.

planetary; → system.

planetary transit
  گذر ِ سیاره‌ای   
gozar-e sayyâre-yi (#)

Fr.: transit planétaire   

The passage of an → inferior planet against the disk of the Sun, as viewed from Earth. Mercury and Venus pass in front of the Sun only when they are close to one of their → orbital nodes, at → inferior conjunction. For Mercury this occurs at the beginning of November (the → ascending node) or at the beginning of May (the → descending node), while for Venus it takes place at the beginning of December (the ascending node) or at the beginning of June (the descending node). See also → transit of Mercury, → transit of Venus.

planetary; → transit.

PLAnetary Transits and Oscillations of stars (PLATO)
  پلاتو   
PLATO

Fr.: PLATO   

A space observatory under development by the → European Space Agency for launch around 2024. Its objective is to detect and characterize → exoplanets by means of their → transit signature in front of a very large sample of → bright stars, and measure the seismic oscillations (→ asteroseismology) of the parent stars orbited by these planets in order to understand the properties of the exoplanetary systems.

planetary; → transit; → oscillation; → star.


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