An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 474

Fr.: hypernova   

A highly energetic → supernova explosion. This phenomenon, which is more violent than a typical → supernova event, is accompanied by a → gamma-ray burst.

hyper-; → nova.

hiperon (#)

Fr.: hypéron   

An unstable elementary particles, belonging to the class called → baryons, which have greater mass than the neutron but very short lives (10-8 to 10-10 seconds).

From → hyper- + → -on a suffix used in the names of elementary particles (gluon; meson; neutron; graviton, and so on).


Fr.: hypersonique   

In aerodynamics, adjective used to describe a → sound speed in excess of Mach 5. See also → supersonic.

Hypersonic, from → hyper- + → sonic.

hypervelocity star (HVS)
  ستاره‌ی ِ هیپرتند   
setâre-ye hipertond

Fr.: étoile hypervéloce   

A star whose velocity is so great that it will escape the → gravitational potential of our → Galaxy. Depending on the location and direction of motion, this criterion typically corresponds to a stellar velocity in the Galactic → rest frame larger than 400 km s-1, and up to about 1200 km s-1. The nature of the HVSs spans a wide range of types from → OB stars, to metal-poor → F-type stars and G/K dwarfs. While there is evidence from many late-type B HVSs in the → halo to originate from the Galactic → supermassive black hole (SMBH), other HVSs seem to originate from the → galactic disk. HVSs can obtain their large velocities from a number of different processes:
1) → Tidal disruption of → close binary stars by the central SMBH of the Milky Way. In this process one star is captured by the SMBH while the other is ejected at high speed via the → gravitational slingshot mechanism.
2) Exchange encounters in other dense stellar environments between hard binaries (→ hard binary) and → massive stars may cause stars to be ejected and escape our Galaxy.
3) Disruption of close binaries via → supernova explosions. The → runaway velocities of both ejected stars can reach large values when asymmetric supernovae are considered, i.e. when the newborn → neutron star receives a momentum kick at birth.
(see, e.g., T. M. Tauris, 2014, and references therein, arXiv:1412.0657).

hyper-; → velocity; → star.


Fr.: hypo-   

A Gk. prefix denoting "under."

Gk. hypo "under" (prep.), "below" (adv.); cognate with L. sub- and O.Pers./Av. upā, as below.

Upâ-, from O.Pers. upā (prep.) "under, with;" Av. upā, upa (prep.; prevb) "toward, with, on, in" (upā.gam- "to arrive at," upāpa- "living in the water," upa.naxturušu "bordering on the night"); Mod.Pers. "with," from abâ; cf. Skt. úpa (adv., prevb., prep.) "toward, with, under, on;" cognate with Gk. hypo, as above.


Fr.: hypocycloïde   

A curve generated by the trace of a fixed point on a small circle that rolls within a larger circle.

Hypocycloid, from → hypo- + → cycloid.

vatar (#)

Fr.: hypoténuse   

In a → right triangle, the side opposite to the right angle.

L.L. hypotenusa, from Gk. hypoteinousa "stretching under" (the right angle), from hypoteinein, from → hypo- "under" + teinein "to stretch," → tension.

Vatar loan from Ar.


Fr.: hypothermie   

The failure of the body to maintain adequate production of heat under conditions of extreme cold.

Hypothermia, from → hypo- + therm, from Gk. therme "heat," from PIE *ghwerm-/*ghworm- "warm;" cf. Pers. garm "warm;" L. fornax "an oven;" O.E. wearm "warm" + -ia a noun suffix.

Upâgarmâyi, from upâ-, → hypo-, + garmâ "heat, warmth," from Mid.Pers. garmâg; O.Pers./Av. garəma- "hot, warm;" cf. Skt. gharmah "heat;" Gk. thermos "warm;" L. formus "warm," fornax "oven;" P.Gmc. *warmaz; O.E. wearm; E. warm; O.H.G., Ger. warm; PIE *ghworm-/*ghwerm- "warm" + -yi noun suffix.

  انگاره، اوپاداین   
engâre (#), upâdâyan

Fr.: hypothèse   

A statement which is based on previous observations and which serves as a starting point for further investigation by which it may be proved or disproved. See also → theory, → model, → ad hoc hypothesis, → Kant-Laplace hypothesis, → arge number hypothesis, → nebular hypothesis, → null hypothesis, → statistical hypothesis, → statistical hypothesis testing.

Hypothesis, from M.Fr. hypothèse, from L.L. hypothesis, from Gk. hypothesis "base, basis of an argument, supposition," literally "a placing under," from → hypo- "under" + thesis "a placing, proposition," from root of tithenai "to place, put, set," didomi "I give;" from PIE base *dhe- "to put, to do;" cf. Mod.Pers. dâdan "to give," Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do."

Engâré, from engâridan, engâštan "to → suppose."
Upâdâyan, from upâ-, → hypo-, + dâyan, → thesis.

  انگاره ساختن، اوپاداینیدن   
engâré sâxtan (#), upâdâyanidan

Fr.: faire une hypothèse   

To form a → hypothesis.

Hypothesize, from hypothes(is), → hypothesis + -ize a verb-forming suffix, from M.E. -isen, from O.Fr. -iser, from L.L. -izare, from Gk. -izein.

Engâré sâxtan, from engâré, → hypothesis + sâxtan, sâzidan "to adapt, adjust, be fit; to build, make, fashion," Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form," Av. sak- "to understand, to mark," sâcaya- (causative) "to teach."
Upâdâyanidan, infinitive from upâdâyan, → hypothesis.

  انگاره‌ای، اوپاداینی   
engâre-yi (#), upâdâyani

Fr.: hypothétique   

Of, pertaining to, or involving a → hypothesis; supposed.

hypothesis; → -al.

pasmând (#)

Fr.: hystérésis   

The phenomenon exhibited by a body (especially a ferromagnetic or imperfectly elastic material) in reacting to changes in the forces, especially magnetic forces, affecting it.
In ferromagnetic materials, the lag in the change in the magnetic induction B behind the change in the intensity of the external magnetizing field, due to the dependence of B on its previous values (past history).

Hysteresis, from Gk. hysteresis "being behind or late," from hystere-, stem of hysterein "to come late, lag behind" + -sis a suffix forming abstract nouns of action.

Pasmând "lagging behind," from pas "behind" (Mid.Pers. pas "behind, before, after;" O.Pers. pasā "after;" Av. pasca "behind (of space); then, afterward (of time);" cf. Skt. pazca "behind, after, later," L. post "behind, in the rear; after, afterward;" O.C.S. po "behind, after;" Lith. pas "at, by;" PIE *pos-, *posko-) + mând stem of mândan "to remain; to be fatigued," mân "house, family" (Mid.pers. mândan "to remain, stay;" O.Pers. mān- "to remain, dwell;" Av. man- "to remain, dwell; to wait;" cf. Gk. menein "to remain;" L. manere "to stay, remain, abide," mansio "a staying, a remaining, night quarters, station" (Fr. maison, ménage; E. manor, mansion, permanent); PIE *men- "to remain, wait for."

hysteresis loop
  گردال ِ پسماند   
gerdâl-e pasmând

Fr.: cycle d'hystérésis   

A closed curve showing the change in magnetic induction of a ferromagnetic body to which an external field is applied as the intensity of this field is varied from +Hs to -Hs and back again, where Hs is the magnetic field intensity corresponding to saturation.

hysteresis; → loop.

hysteresis loss
  دست‌رفت ِ پسماندی   
dastraft-e pasmândi

Fr.: perte par hystérésis   

Dissipation of energy which occurs, due to magnetic hysteresis, when the magnetic material is subject to changes of magnetization.

hysteresis; → loss.

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