An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 391
  ۱) مداری؛ ۲) مدارال   
1) madâri; 2) madârâl

Fr.: 1) orbital; 2) orbitale   

1) Of or relating to an orbit.
2) A wave function that describes the state of an electron with a given energy (n, l, and ml quantum numbers) in an atom (atomic orbital) or in a molecule (molecular orbital).

Orbital, from → orbit + → -al.

orbital angular momentum
  جنباک ِ زاویه‌ای ِ مداری   
jonbâk-e zâviyeyi-ye madâri

Fr.: moment cinétique orbital, ~ angulaire ~   

1) Mechanics: The → angular momentum associated with the motion of a particle about an origin, equal to the cross product of the position vector (r) with the linear momentum (p = mv): L = r x p. Although r and p are constantly changing direction, L is a constant in the absence of any external force on the system. Also known as orbital momentum.
2) Quantum mechanics: The → angular momentum operator associated with the motion of a particle about an origin, equal to the cross product of the position vector with the linear momentum, as opposed to the → spin angular momentum. In quantum mechanics the orbital angular momentum is quantized. Its magnitude is confined to discrete values given by the expression: ħ &radic l(l + 1), where l is the orbital angular momentum quantum number, or azimuthal quantum number, and is limited to positive integral values (l = 0, 1, 2, ...). Moreover, the orientation of the direction of rotation is quantized, as determined by the → magnetic quantum number. Since the electron carries an electric charge, the circulation of electron constitutes a current loop which generates a magnetic moment associated to the orbital angular momentum.

orbital; → angular; → momentum.

orbital axis
  آسه‌ی ِ مداری   
âse-ye madâri

Fr.: axe orbital   

The → perpendicular to the → orbital plane.

orbital; → axis.

orbital debris
  تیفالِ مداری   
tifâl-e madâri

Fr.: débris spatial   

Objects in orbit around Earth created by humans, that no longer serve any useful purpose. They consist of everything from entire spent rocket stages and defunct satellites to explosion fragments, paint flakes, dust, and slag from solid rocket motors, and other small particles. Also called space junk and space waste.

orbital; → debris .

orbital electron
  الکترونِ مداری   
elektron-e madâri (#)

Fr.: électron orbital   

An electron contained within an atom which may be thought of as orbiting around the nucleus, in a manner analogous to the orbit of a planet around the Sun.

orbital; → electron .

orbital element
  بُن‌پارِ مداری   
bonpâr-e madâri

Fr.: élément orbital   

Any of the six parameters needed to specify the → orbit of an object around a → primary body (such as a planet around the Sun or a satellite around the Earth) and give its position at any instant. Two of them define the size and the form of the orbit: → semi-major axis (a) and → eccentricity (e). Three angular values determine the orbit position in space: the → inclination (i) of the object's → orbital plane to the reference plane (such as the → ecliptic), the → longitude of ascending node (Ω), and the → argument of periapsis (ω). And finally the sixth element is the → time of periapsis passage which allows calculating the body's position along the orbit at any instant.

orbital; → element.

orbital energy
  کاروژِ مداری   
kâruž-e madâri

Fr.: énergie orbitale   

The → sum of the → potential energy and the → kinetic energy of an object in → orbit.

orbital; → energy.

orbital inclination
  درکیلِ مداری   
darkil-e madâri

Fr.: inclinaison orbitale   

An → orbital element that defines the angle between the orbital plane of a solar system body (planet, comet, asteroid) and the plane of the ecliptic. The orbital inclination of the Earth's orbit is 0°; those of Mercury, Venus, and Mars are 7.01°, 3.39°, and 1.85° respectively.

orbital; → inclination .

orbital maneuver
  مانوور ِ مداری   
mânovr-e madâri

Fr.: mainoeuvre orbitale   

The moving of a spacecraft between two different orbits resulting from a change in its velocity (acceleration). Generally, manoeuvres are caused by → thrust from the spacecraft's motors.

orbital; → maneuver.

orbital manoeuvre
  مانوور ِ مداری   
mânovr-e madâri

Fr.: mainoeuvre orbitale   

orbital maneuver.

orbital; → manoeuvre.

orbital migration
  کوچِ مداری   
kuc-e madâri

Fr.: migration orbitale   

Theoretical prediction according to which a → giant planet, formed in the outer regions of a → protoplanetary disk, could migrate inward by losing → energy and → angular momentum as the result of → gravitational interactions with the remnants of the disk. This orbital migration could explain the presence of giant gaseous Jupiter-like planets (→ hot Jupiters) very close to their host stars.

orbital; → migration.

orbital node
  گره ِ مداری   
gereh-e madâri

Fr.: nœud orbital   

One of the two points of intersection of the orbit of a secondary body with the plane of reference through the primary.

orbital; → node.

orbital period
  دوره‌یِ مداری   
dowre-ye medâri (#)

Fr.: période orbitale   

The time interval between two successive passages of an object through the same point in its orbit around another object.

orbital; → period .

orbital phase
  فاز ِ مداری   
fâz-e madâri

Fr.: phase orbitale   

In → photometry of → binary stars or → two-body systems, the number of whole or fractional orbits completed, from the point the photometry begins. The point is conventionally chosen as the position at which the → primary star eclipses the → secondary star, and therefore the → light curve is at a minimum. The phase keeps counting indefinitely, thus the secondary star gets eclipsed at phase 0, 1, 2, 3, and so on. At these phases the primary lies between the secondary and the observer. An orbital phase of 0.5 corresponds to halfway through the binary orbit, 0.75 is three-quarters the way through, and so on.

orbital; → phase.

orbital phase curve
  خم ِ فاز ِ مداری   
xam-e fâz-e madâri

Fr.: courbe de la phase orbitale   

The photometric variability induced by the → orbital motion in a → two-body system.

orbital; → phase.

orbital plane
  هامُنِ مداری   
hâmon-e madâri

Fr.: plan orbital   

The plane defined by the motion of an object about a primary body.

orbital; → plane .

orbital precession
  پیشایان ِ مداری   
pišâyân-e madâri

Fr.: précession orbitale   

Same as → relativistic precession.

orbital; → precession.

orbital resonance
  باز‌آوایی ِ مداری   
bâzâvâyi-ye madâri

Fr.: résonance orbitale   

The situation in which two orbiting objects exert a regular, periodic gravitational influence on each other and therefore their orbital frequencies are related by a ratio of two small → integers. Orbital resonance often results in an unstable interaction in which bodies exchange momentum and shift orbits until the resonance disappears. The resonance increases the eccentricity until a body approaches a planet too closely and the body is slung away.

orbital; → resonance.

orbital shrinkage
  درهم‌کشیدگیِ مداری   
darhamkešidegi-ye madâri

Fr.: rétrécissement de l'orbite   

The lessening in size of the orbit of a binary system composed of two compact objects (pulsars/black holes) due to loss of energy by the system, in particular through gravitational wave radiation. This loss will cause the two objects to approach closer to each other, the orbital period decreases and the binary companions will eventually merge.

orbital; shrinkage, from shrink, from M.E. schrinken, O.E. scrincan, from P.Gmc. *skrenkanan (cf. M.Du. schrinken, Swed. skrynka "to shrink."

Darhamkešidegi "shrinking, shriveling," from state noun of < i>darhamkešidé, from darham- "together, in eachother, toward eachother" (For etymology of dar-, → in-; for etymology of ham-, → com-) + kešidé "drawn, shrivelled, wrinkled," from Mod./Mid.Pers. kešidan, kašidan "to draw, protract, trail, drag, carry," dialectal Yaqnavi xaš "to draw," Qomi xaš "streak, stria, mark," Lori kerr "line;" Av. karš- "to draw; to plow," karša- "furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;" cf. Skt. kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base kwels- "to plow;" madâri, → orbital.

orbital speed
  تندای ِ مداری   
tondâ-ye madâri

Fr.: vitesse orbitale   

Same as → orbital velocity.

orbital; → speed.

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