An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ic ice ide ima imp imp inc ind ind ine inf inf inf ini ins ins int int int int int int int int inv ion Iot irr iso iso iso > >>

Number of Results: 611
isobaric spin
isospin (#)

Fr.: spin isobarique   

Same as → isospin.

Isobaric, adj. of → isobar; → spin.

isochoric process
  فراروند ِ ایزوگنج   
farâravand-e izogonj

Fr.: processus isochore   

A process in which the volume remains unchanged.

From → iso- + chor-, from Gk. chora "place, land" + → ic.

Farâravand, → process; izogonj, from izoiso- + gonj "volume," gonjdan "to be contained; to hold exactly; to be filled;" Mid.Pers. winj- "to be contained;" Proto-Iranian *uiac-/*uic-; cf. Skt. vyac- "to contain, encompass," vyás- "extent, content, extension;" L. uincire "to bind."


Fr.: isochrone   

A curve on a → Hertzsprung-Russell diagram connecting all stars having the same age.

Isochrone, back formation from isochronal, from Gk. → iso- + khronos "time."

Izozamân, from → iso- + zamântime.


Fr.: isogonal   

Having similar angles.

iso- + -gonal, → diagonal

isogonal trajectory
  ترایشانه‌ی ِ ایزوکنج   
tarâyešâne-ye izokonj

Fr.: trajectoire isogonale   

Math.: A curve which intersects every member of a given one-parameter family of curves at one and the same angle.

isogonal; → trajectory.


Fr.: isohel   

Line joining geographical points of equal insolation during a specific interval of time.

From Gk. → iso- + hel, from helios "sun," → helio-.

Izohur, from izo-, → iso-, + hur "sun," cognate with → helio-.

isokinetic angle
  زاویه‌ی ِ ایزوجنبشی   
zâviye-ye izojonbeši

Fr.: angle isocinétique   

Adaptive optics: The angle over which wavefront phases become de-correlated by 1 radian rms due to → tip-tilt alone. It is defined analogously to the → isoplanatic angle.

iso-; → kinetic; → angle.


Fr.: isoler   

To set or place apart; detach or separate so as to be alone.
Chemistry: To obtain a substance in an uncombined or pure state.
Physics: → isolated system.

Isolate, back-formation from isolated, from Fr. isolé "isolated," from It. isolato, from L. insulatus "made into an island," from insula "island;" maybe from *en-salos "in the sea," from salum "sea."

Vâyutidan, from vâ- denoting "separation" (also "reversal, opposition; repetition; back, backward," variant of bâz-, from Mid.Pers. abâz-, apâc-; O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind") + Mid.Pers. yut "separate, different," Mod.Pers. jodâ "separate, apart;" Av. yuta- "separate, apart" + -idan infinitive suffix.


Fr.: isolé   

Set apart or separated from others or other things.

Past participle of → isolate.

isolated galaxy
  کهکشان ِ وایوتیده   
kahkešân-e vâyutidé

Fr.: galaxie isolée   

A galaxy that is not a member of a dense aggregate. In other words, a galaxy that is formed in a low galactic density environment and has evolved without major interactions with other galaxies of similar mass.

isolated; → galaxy.

isolated massive star formation
  دیسش ِ وایوتیده‌ی ِ ستاره‌ی ِ پرجرم   
diseš-e vâyutide-ye setâre-ye porjerm

Fr.: formation isolée d'étoile massive   

Massive star formation outside → OB associations. Recent observational findings suggest that → massive star formation is a collective process. In other words, massive stars form in → cluster environments and the mass of the most massive star in a cluster is correlated with the mass of the cluster itself. Nevertheless, other observational results give grounds for supposing that massive stars do not necessarily form in clusters but that they can be formed as isolated stars or in very small groups. According to statistical studies nearly 95% of Galactic → O star population is located in clusters or OB associations. This means that a small percentage, about 5%, of high mass stars may form in isolation. Isolation is meant not traceable to an origin in an OB association. This definition therefore excludes → runaway massive stars, which are thought to result from either dynamical interaction in massive dense clusters, or via a kick from a → supernova explosion in a → binary system. Alternatively, isolated massive star has been defined as follows: An O-type star belonging to a cluster whose total mass is < 100 Msun and moreover is devoid of → B stars (Selier et al. 2011, A&A 529, A40 and references therein).

isolated; → massive star; → formation.

isolated neutron star (INS)
  ستاره‌ی ِ نوترونی ِ وایوتیده   
setâre-ye notroni-ye vâyutidé

Fr.: étoile à neutron isolée   

A → neutron star which does not belong to a → binary system, does not have radio emission, and is not surrounded by a progenitor → supernova remnant. INSs appear to be thermally cooling with no emission outside the → soft X-ray band, except for faint optical/UV counterparts. Although these properties are similar to those of → compact central object (CCO)s, they are a distinct class because they lack any observable associated supernova remnant or nebula. There are presently seven confirmed INSs (sometimes referred to as The Magnificent Seven), six of which have measured weakly modulated X-ray pulsations with periods between 3 s and 11 s, much longer than those of CCOs (A. K. Harding, 2013, Front. Phys. 8, 679).

isolated; → neutron; → star.

isolated system
  راژمان ِ وایوتیده   
râžmân-e vâyutidé

Fr.: système isolé   

Thermodynamics: A system which has no exchange of energy or matter with surroundings. The internal energy of such a system remains constant. → closed system; → open system.

isolated; → system.


Fr.: isolation   

An act or instance of isolating; the state of being isolated.

Verbal noun of → isolate.

izomer (#)

Fr.: isomère   

Physics: Any of two or more nuclei having the same atomic number A and mass number Z but different half-lives.
Chemistry: One of two or more substances that have the same chemical composition but differ in structural form.

Back formation from isomeric, from → iso- + mer a combining form meaning "part," from Gk. meros "part, portion, share."

Izomer, loan from Fr. isomère.


Fr.: isomorphisme   

A one-to-one → mapping between two → sets, which preserves the relations existing between elements in its → domain. An isomorphism is a → bijective morphism.

iso-; → morphism.


Fr.: isonèphe   

A line drawn through all points on a weather map having the same amount of → cloud cover.

From Gk. → iso- + nephos "cloud," cognate with Pers. nam "humidity, moisture;" Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" Skt. nábhas- "moisture, cloud, mist;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" from PIE *nebh- "cloud, vapor, fog, moist, sky."

Izoabr, from izo-, → iso-, + abr → cloud.


Fr.: isophotal   

Of or relating to → isophotes.

isophote; → -al.

isophotal radius
  شعاع ِ ایزوشیدی   
šo'â'-e izošidi

Fr.: rayon isophotal   

The size attributed to a galaxy corresponding to a particular level of → surface brightness. The reason is that galaxies do not have sharp edges.

isophotal; → radius.


Fr.: isophote   

A line joining points with the same surface brightness on a plot or in image of a celestial object such as a nebula or galaxy.

Isophote, from → iso- + a combining form of Gk. phos (gen. photos) "light."

Izošid, from izo-, → iso-, + šid "light, sunlight," from Mid.Pers. šêt "shining, radiant, bright;" Av. xšaēta- "shining, brilliant, splendid, excellent."

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