An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 403
osculating elements
  بن‌پارهایِ آبوسشی   
bonpârhâ-ye âbuseš

Fr.: éléments orbitaux osculateurs   

The orbital elements of an osculating orbit.

osculating; → element.

osculating orbit
  مدارِ آبوسنده   
madâr-e âbusandé

Fr.: orbite osculatrice   

The Keplerian orbit that a satellite would follow after a specific time t if all forces other than central inverse-square forces ceased to act from time t on. An osculating orbit is tangent to the real, perturbed, orbit and has the same velocity at the point of tangency.

osculating; → orbit.

osculating plane
  هامُنِ آبوسنده   
hâmon-e âbusandé

Fr.: plan osculateur   

For a curve C at a point p, the limiting plane obtained from taking planes through the tangent to C at p and containing some variable point p' and then letting p' approach p along C.

osculating; → plane.

osculating sphere
  سپهرِ آبوسنده، کره‌یِ آبوسنده   
sepehr-e âbusandé, kore-ye ~

Fr.: sphère osculatrice   

For a curve C at a point p, the limiting sphere obtained by taking the sphere that passes through p and three other points on C and then letting these three points approach p independently along C.

osculating; → sphere.


Fr.: osculation   

The contact between two osculating curves or the like.

Verbal noun of → osculate


Fr.: OSIRIS-REx   

A → spacecraft whose goal is to collect a sample from the asteroid → 101955 Bennu and bring it back to Earth. It was launched by → NASA on September 8, 2016. OSIRIS-REx will spend two years chasing Bennu down, finally rendezvousing with the → near-Earth asteroid in August 2018. The spacecraft will then study the → asteroid Bennu from orbit for another two years before grabbing at least 60 grams of surface material in July 2020. The sample should reach Earth in 2023. The analysis of the sample would allow to study the role that → B-type asteroids like Bennu, which are primitive and apparently carbon-rich, may have played in helping life appear on Earth.

The name is short for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer .


Fr.: osmium   

A very hard, brittle metal belonging to the → platinum group elements; symbol Os. → Atomic number 76, → atomic weight 190.2, → melting point 3,045 °C, → boiling point 5,027 °C, → specific gravity 22.57 at 20°C. It was discovered in 1803 simultaneously with → iridium in a crude → platinum ore by the English chemist Smithson Tennant.

From Gk. osme "smell" because of the sharp odor of the volatile oxide.


Fr.: osmose   

The process by which solvent molecules pass through a partially permeable membrane from a dilute solution into a more concentrated solution, thus equalizing the concentrations of materials on either side of the membrane. → permeability.

Extracted from Fr. endosmose "endosmosis" and exosmose "exosmosis," from Gk. prefixed osmos "a thrusting, a pushing," from othein "to push, to thrust;" cf. Av. vādāiiôit "breaks through, hunts," vadah- "wedge;" Mod.Pers. guvah, gavah "wedge;" Skt. vadh- "to slay, kill," vadha- "killer."

Tarârân, literally "pushing across," from tarâ-, → trans-, + rân present stem of rândan "to push, drive, cause to go," causative of raftan "to go, walk, proceed" (present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

osmotic pressure
  فشارِ ترارانی   
fešâr-e tarârâni

Fr.: pression osmotique   

The hydrostatic pressure produced on the surface of a partially permeable membrane by osmosis.

osmotic; → pressure.

Ostriker-Peebles criterion
  سنجیدار ِ استرایکر-پیبلس   
sanjidâr-e Ostriker-Peebles

Fr.: critère d'Ostriker-Peebles   

An approximate empirical criterion for the stability of a → galactic disk against its collapse to form a bar. The disk is stable if the following relation holds: T/|W| < 0.14, where T is the rotational → kinetic energy and |W| is the absolute value of the gravitational → potential energy. While the → Toomre criterion applies only to small linear perturbations, the Ostriker-Peebles criterion describes global modes.

Ostriker & Peebles, 1973, ApJ 186, 467; → criterion.

  برون، اُس-   
borun, os-

Fr.: hors   

Away from, or not in, the normal or usual place, position, state, etc.

O.E. ut; (cf. O.N., O.Fris., Goth. ut, Du. uit, Ger. aus; PIE base *ud- "up, up away" (cf. Pers. os-, as below; Gk. hysteros "the latter;" L. usque "all the way to, without interruption;" O.Ir. ud- "out;" Rus. vy- "out").

Borun, variant birun "out, the outside," from Mid.Pers. bêron, from "outside, out, away," variant bêg, as in bêgânag (cf. Sogh. bêk "out, outside, apart, except," bêk-dênê "heretic," literally "out of religion") + rôn "side, direction;" Av. ravan- "(course of a) river").
Os-, from Mid.Pers. us-, uz-; Av. uz-, us- "out of, outside, from;" O.Pers. ud- (ud-apatatā "to rise up, rebel"), also Pers. preposition az "from; of; out of," prefixes zo- (in zodudan "to polish, clean;" Mid.Pers. uzdâtan; Av. uzdā-, from uz- + dā- "to make, create"), âz- (âzmâyeš, → experiment), haz- (haziné "cost, expenditure;" Mid.Pers. uzên, uzênak, from *uz-ayana- "going out;" Av. us- + ay- "to go" (→ assembly); PIE *ud- "up, out," cf. Skt. úd "up, away, out;" E. out, as above.

out of phase
  نافاز، ناهم‌فاز   
nâfâz, nâ-ham-fâz

Fr.: déphasé   

The condition of two oscillators that have the same frequency but different phases. Opposed to → in phase.

out; → phase.

  ا ُسبلک   

Fr.: sursaut   

1) A fairly brief period of unusually strong gas and/or dust production from a comet nucleus.
2) A brief period of enhancement of emission from a star, a quasar, etc.

out; → burst.

outburst decay
  تباهی ِ اسبلک   
tabâhi-ye osbelk


A phase in the → light curve evolution of eruptive objects such as → dwarf novae, → Soft X-ray Transients, and transient → magnetars which follows the characterized sudden increase in their flux (over a factor ~ 1000 over the quiescent level). Outburst decay is slow and lasts months or years.

outburst; → decay.

borunšod (#)

Fr.: issue, résultat   

A final product or end result; consequence; issue (

out; → come.

Borunšod "outcome," from borun, → out, + šod, šodan "to go, to pass, to change," → become.

borunzad (#)

Fr.: affleurement   

Emergence of a particular rock-body, e.g. a stratium or vein, at the ground surface. Outcrops can be formed naturally or by human action. Stream erosion and highway construction can produce outcrops.

Noun use of crop out, from crop, from M.E., O.E. cropp "bird's craw," also "head or top of a sprout or herb;" → out.

Borunzad, literally "strike out," from borun, birun, → out, + zad, zadan "to strike, beat," from Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill."

biruni (#)

Fr.: externe   

Being or located on or toward the outside; external.

out + -er suffix of comparative degree of adjectives.


outer core
  مغزه‌ی ِ بیرونی   
maqze-ye biruni

Fr.: noyau externe   

The upper zone of the → Earth's core, just below the → mantle, extending from a depth of about 2900 km to 5100 km. It is presumed to be → liquid because it sharply reduces → compressional wave velocities and does not transmit → shear waves. Its density is from 9 to 11 g/cm3. The → temperature ranges from 4400 °C in the outer areas to 6100 °C near the → inner core. Since shear waves do not propagate through a fluid, the Earth's outer core is considered to be liquid because the shear wave velocity is zero. Convection motion within the outer core, along with the rotation of the Earth creates an effect that maintains the Earth's → magnetic field.

outer; → core.

outer Lindblad resonance (OLP)
  باز‌آوایی ِ لیندبلاد ِ برونی   
bâzâvâyi-ye Lindblad-e boruni

Fr.: résonance de Lindblad externe   

A → Lindblad resonance expressed by: Ωp = Ω + κ/m.

outer; → Lindblad resonance.

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.

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