An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 25 Search : planetary
born-again planetary nebula
  میغ ِ سیاره‌ای ِ باز‌زاد   
miq-e sayâreyi-ye bâzzâd

Fr.: nébuleuse planétaire recyclée   

A → planetary nebula which is thought to have experienced a → very late thermal pulse (VLTP) when the central star (→ CSPN) was on the → white dwarf cooling track. The VLTP event occurs when the thermonuclear → hydrogen shell burning has built up a → shell of helium with the critical mass to ignite its → fusion into carbon and oxygen (→ helium shell burning). Since the → white dwarf envelope is shallow, the increase of pressure from this last helium shell flash leads to the ejection of newly processed material inside the old planetary nebula, leaving the stellar core intact. As the stellar envelope expands, its → effective temperature decreases and the star goes back to the → asymptotic giant branch (AGB) region in the → H-R diagram. The subsequent stellar evolution is fast and will return the star back to the → Post-AGB track in the H-R diagram: the envelope of the star contracts, its effective temperature and ionizing photon flux increase, and a new fast stellar wind develops (see, e.g. J. A. Toalá et al. 2015, ApJ 799, 67).

born; → again; → planetary; → nebula.

compact planetary nebula B[e] star (cPNB[e])
  ستاره‌یِ B[e]ی ِ میغ ِ سیاره‌ای ِ همپک   
setâre-ye B[e]-ye miq-e sayyâre-yi-ye hampak

Fr.: étoile de nébuleuse planétaire compacte   

A star whose spectrum shows striking similarities to → B[e] stars and is evolving into a → planetary nebula (→ preplanetary nebula).

compact; → planetary; → nebula; → B[e] star.


Fr.: exoplanétaire   

Of, relating to, or resembling an → exoplanet or exoplanets.

exoplanet; → -ary.

exoplanetary system
  راژمان ِ برون‌سیاره‌ای   
râſmân-e borun-sayyâre-yi

Fr.: système exoplanétaire   

A → planetary system consisting of → exoplanets orbiting a star other than Sun.

exoplanetary; → system.

interplanetary coronal mass ejections (ICME)
  اشانش ِ اندرسیاره‌ای ِ جرم از تاج   
ešâneš-e andarsayyâreyi-ye jerm az tâj

Fr.: éjection de masse coronale interplanétaire   

An → interplanetary manifestation of a → coronal mass ejection.

interplanetary; → coronal; → mass; → ejection.

interplanetary dust
  غبار ِ اندرسیاره‌ای   
qobâr-e andarsayyâreyi

Fr.: poussière interplanétaire   

Particles of dust in the → interplanetary medium. They are left-overs from the beginning of the solar system or from other sources such as sublimating comets. Their existence was first deduced from observations of → zodiacal light.

interplanetary; → dust.

interplanetary gas
  گاز ِ اندرسیاره‌ای   
gâz-e andarsayyâreyi

Fr.: gaz interplanétaire   

Electrically charged particles of the solar wind and gas liberated from comets within the solar system.

interplanetary; → gas.

interplanetary magnetic field
  میدان ِ مغناتیسی ِ اندرسیاره‌ای   
meydân-e meqnâtisi-ye andarsayyârei

Fr.: champ magnétique interstellaire   

The magnetic field that is carried along with the solar wind and fills the solar system space. It is wound into a spiral structure by the rotation of the Sun. At the Earth's distance from the Sun, it has a strength of about 5 x 10-5 gauss.

interplanetary; → magnetic; → field.

interplanetary matter
  مادّه‌ی ِ اندرسیاره‌ای   
mâdde-ye andarsayyâreyi

Fr.: matière interplanétaire   

Material existing in the space between solar system planets. It includes interplanetary gas and dust.

interplanetary; → matter.

interplanetary medium
  مدیم ِ اندرسیاره‌ای   
madim-e andarsayâre-yi

Fr.: milieu interplanétaire   

The material contained in the → solar system in the space through which the planets travel. It consists of the smaller objects such as → asteroids, → comets, → meteorites and also a general pervading → interplanetary dust. Moreover a → plasma of charged particles streaming outward from the Sun in the form of the → solar wind contributes to the interplanetary medium.

interplanetary; → medium.

interplanetary space
  فضای ِ اندرسیاره‌ای   
fazâ-ye anadrsayyâre-yi

Fr.: espace interplanétaire   

Same as → interplanetary medium.

interplanetary; → space.

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
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.

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