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.
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.
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.
Fr.: plan orbital
The plane defined by the motion of an object about a primary body.
Fr.: précession orbitale
Same as → relativistic precession.
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.
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.
Fr.: vitesse orbitale
The velocity of an object in a given orbit around a gravitating mass. For a perfect circular orbit, the velocity is described by the formula V =√[G(M + m)/r], where G is the gravitational constant, M the mass of the primary gravitating body, m the mass of the orbiting object, and r the radius of the orbit.
In astronautics, the study of satellite orbits and precise determination of orbital elements which gives the exact position of the satellite.
1) râyé; 2) râyândan
Fr.: 1) ordre; 2) ordonner
1a) General: The way in which several items are arranged, as an indication
of their relative importance or size or when each will be dealt with.
From O.Fr. ordre, from earlier ordene, from L. ordinem (nominative ordo) "row, rank, arrangement."
Râyé, noun related to râyânidan "to regulate, set in order," from Mid.Pers. râyânīdan "to arrange, organize," from rây- (Mod.Pers. ârây-, ârâyeš, ârâyidan "to arrange, adorn"), ârây-, ârâstan "to arrange, adorn;" O.Pers. rād- "to prepare," rās- "to be right, straight, true," rāsta- "straight, true" (Mod.Pers. râst "straight, true"); Av. rāz- "to direct, put in line, set," razan- "order;" Gk. oregein "to stretch out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" Skt. rji- "to make straight or right, arrange, decorate;" PIE base *reg- "move in a straight line;" see also → direct.
order of a tensor
Fr.: ordre de tenseur
The maximum number of the indices (→ index) of a tensor.
order of interference
Fr.: ordre d'interfrérence
A whole number which characterizes a particular position of an interference fringe according to whether there is interference arising from one, two, three, etc. wavelength difference of path. Same as → interference order
order of magnitude
Fr.: ordre de grandeur
Value of a number or of a physical quantity given roughly, usually expressed as a power of 10. Thus, 2.5 x 105 and 6.4 x 105 are of the same order of magnitude, and 2 x 107 is 2 orders of magnitude greater than either.
1) Of or relating to an order, as of animals or plants.
Fr.: nombre ordinal
1) A number which defines the position or rank of something in a series, in contrast to
→ cardinal number. For example, first,
second, tenth, etc.
M.E. ordinarie, from O.Fr. ordinarie, from L. ordinarius "regular, usual, orderly," from ordo (genitive ordinis) "order" + -arius-ary.
Šunik "ordinary," from Mid.Pers. šônik, šônig "ordinary, customary," from šôn "kind, manner, sort, way" + -ik, → -ic.
ordinary differential equation
hamugeš-e degarsâneyi-ye šunik
Fr.: équation différentielle ordinaire
Fr.: point ordinaire
The point M0(x0,y0) of the curve F(x,y) = 0, where at least one of the partial derivatives ∂F/∂x and ∂F/∂y does not vanish. → singular point
Fr.: rayon ordinaire
Fr.: année ordinaire