An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 13048 Search : far
violation
  اناه، اناهش   
enâh, enâheš

Fr.: violation   

The act of violating. The state of being violated. → parity violation

Verbal noun from → violate.

violent
  سورا   
surâ

Fr.: violent   

Intense in force, effect; severe; extreme.
See also: → optically violent variable (OVV) quasar, → violent galaxy, → violent interstellar environment, → violent relaxation, → violent star formation.

M.E., from O.fr. violent, from L. violentus "vehement, forcible."

Surâ, from Av. sūra- "strong, powerful, mighty;" cf. Skt. śūra- "strong, powerful, valiant."

violent galaxy
  کهکشان ِ سورا   
kahkašân-e surâ

Fr.: galaxie violente   

A type of galaxy that releases a tremendous amount of energy, on the average 1058 ergs, compared with a supernova release of 1049 ergs. Violent galaxies include quasars and exploding galaxies. About 1 percent of the galaxies are classified as violent. The nearest violent galaxy is Cen A.

violent; → galaxy.

violent interstellar environment
  پرگیر ِ اندر-اختری ِ سورا   
pargir-e andar-axtari-ye surâ

Fr.: environnement interstellaire violent   

A description of the interstellar medium justified by the presence of supersonic shock waves, massive star winds, turbulence, supernova explosions, etc.

violent; → interstellar; → environment.

violent relaxation
  واهلش ِ سورا   
vâhaleš-e surâ

Fr.: relaxation violente   

A process in which a dynamical system made up of many objects (star cluster, galaxy cluster) rapidly relaxes from a chaotic initial state to a quasi-equilibrium.

violent; → relaxation.

violent star formation
  دیسش ِ سورای ِ ستارگان   
diseše surâ-ye setâregân

Fr.: formation violente d'étoiles   

The concept of star formation pertaining to a variety of systems (OB associations, giant H II regions, H II galaxies, massive star clusters, etc.) that are believed to have formed large numbers of stars in a very short time.

violent; → star formation.

violet
  بنفش   
banafš (#)

Fr.: violet   

A color at the opposite end of the visible spectrum from red, an effect of light with a wavelength between 4000 and 4500 Å. → ultraviolet.

M.E., from O.Fr. violete, diminutive of viole "violet," from L. viola, akin to Gk. ion "violet."

Banafš "violet," related to banafšé "violet flower;" Mid.Pers. vanafšak "violet flower."

violet layer
  لایه‌ی ِ بنفش   
lâye-ye banafš

Fr.: couche violette   

A layer of particles in the upper Martian atmosphere that scatter and absorbs electromagnetic radiation at shorter wavelengths, making the atmosphere opaque to blue, violet, and ultraviolet light.

violet; → layer.

Virgo
  دوشیزه   
Dušizé (#)

Fr.: Vierge   

The Maiden. A large constellation of the Zodiac, situated at the celestial equator with 13h right ascension, 2° south declination. The brightest star is the first magnitude → Spica, and there are seven others brighter than fourth magnitude. Because of the presence of a background galaxy cluster, → Virgo cluster, this constellation is especially rich in galaxies. Eleven of the brighter galaxies are listed in the → Messier catalog. Abbreviation: Vir; Genitive: Virginis.

L. virgo "maiden, unwedded girl or woman."

Dušizé "maiden, virgin;" Mid.Pers. dôšizag "maiden, virgin," related to duxtar, duxt "daughter" (O.Pers. *duxçi-; Av. dugədar-, duγdar-; cf. Skt. duhitár-, Gk. thygater; E. daughter; Ger. Tochter; PIE base *dhug(h)əter-); Manichean Mid.Pers. duxš "princess, girl of noble birth;" O.Pers. duxši- (Elamite du-uk-ši-iš) "royal princess" + diminutive suffix -izag, -izé (as in suffixed Fr. demoiselle, from V.L. *dominicella, from domin(a) "lady" + -i- + -cella diminutive suffix).

Virgo A
  دوشیزه A   
Dušizé A

Fr.: Virgo A   

The most powerful radio source in the constellation Virgo, among the thousands of galactic systems comprising the → Virgo Cluster. Optically, it is an elliptical galaxy (M87) with a luminous blue jet about 1500 pc long. It is also an X-ray source (3C 274, Virgo X-1, 2U 1228+12).

Virgo.

Virgo cluster
  خوشه‌ی ِ دوشیزه   
xuše-ye dušizé

Fr.: amas de la Viege   

The largest and nearest galaxy cluster to the Local Group. The Virgo cluster spans 120 square degrees on the sky and contains on the order of 2,000 galaxies. It is located at a distance of about 60 million light-years. It is an irregular cluster with no central concentration. The giant elliptical galaxy M87 is the most massive in the cluster.

Virgo; → cluster.

Virgo interferometer
  اندرزنش‌سنج ویرگو   
andarzaneš-sanj Virgo

Fr.: interféromètre Virgo   

A → Michelson interferometer using → laser beams designed to detect → gravitational waves. It consists of two 3-km-long arms, which house the various machinery required to form a → laser interferometer. The gravitational waves searched for have frequencies between 10 Hz and 10 kHz. Virgo has been designed and built by a collaboration between the French Centre National de la Recherche Scientifique (CNRS) and the Italian Istituto Nazionale di Fisica Nucleare (INFN). It is now operated and improved in Cascina, a small town near Pisa on the site of the European Gravitational Observatory (EGO), by an international collaboration of scientists from France, Italy, the Netherlands, Poland, and Hungary. The initial Virgo detector observed the sky between 2007 and 2011 together with the two interferometers of the → Laser Interferometer Gravitational-Wave Observatory (LIGO), located in the United States. Virgo underwent a major upgrade after a long shutdown period. The "Advanced Virgo" overhaul lasted 5-year and costed 23 million Euros. The upgraded observatory was inaugurated on 20 February 2017 and, notably, detected the → GW170817 event.

Named after the → Virgo cluster of galaxies whose stellar explosions it aims to detect; → interferometer.

Virgo supercluster
  اَبَر-خوشه‌ی ِ دوشیزه   
abar-xuše-ye Dušizé

Fr.: superamas de la Vierge   

The irregular supercluster that contains the Virgo cluster and the Local Group. At least 100 galaxy groups and clusters are located within its diameter of 110 million light-years. It is one of millions of superclusters in the observable Universe.

Virgo; → supercluster.

virial
  ویریال   
viriyâl

Fr.: viriel   

Of or pertaining to the interactive forces between components of a system, such as particles or molecules in a gas or stars in a cluster.
virial equation of state, → virial equilibrium, → virial mass, → virial parameter, → virial radius, → virial temperature, → virial theorem, → virialization.

From L. vires, plural of vis "strength," and by extension "force" or "energy," first used by Rudolf Clausius in the investigation of problems in molecular physics.

Viriyâl, loan from E., as above.

virial equation of state
  هموگش ِ حالت ِ ویریال   
hamugeš-e hâlat-e viriyal

Fr.: équation d'état du viriel   

In thermodynamics, a generalized → equation of state obtained when the → compression factor Z is expanded in terms of a power series, e.g.: Z = 1 + B(T) / Vm + C(T) / Vm2 + ...

virial; → equation of state.

virial equilibrium
  ترازمندی ِ ویریال   
tarâzmandi-ye viriyâl

Fr.: équilibre du viriel   

The condition of a physical system which obeys the → virial theorem.

virial; → equilibrium.

virial mass
  جرم ِ ویریال   
jerm-e viriyâl

Fr.: masse du viriel   

The mass of a cluster of stars or galaxies in statistical equilibrium derived by using the → virial theorem.

virial; → mass.

virial parameter
  پارامون ِ ویریال   
pârâmun-e viriyâl

Fr.: paramètre du viriel   

A dimensionless parameter that measures the ratio of thermal plus kinetic energies to gravitational energy of a physical system, such as a molecular cloud. The virial parameter is expressed as: αvir = 5σ2R / GM, where R and M are the radius and mass of the cloud respectively, σ is the one-dimensional → velocity dispersion inside the cloud, and G the → gravitational constant. It indicates whether a cloud could be bound or not. For molecular clouds that are confined by their surface pressure and for which self-gravity is unimportant, αvir is much larger than unity, whereas αvir is ~ 1 when the gravitational energy of a clump becomes comparable to its kinetic energy. See, e.g., Bertoldi & McKee, 1992 (ApJ 395, 140). See also → virial theorem.

virial; → parameter.

virial radius
  شعاع ویریال   
šo'â'-e viriyâl

Fr.: rayon du viriel   

The radius centered on a galaxy containing matter at 200 times the → critical density of the Universe.

virial; → radius.

virial temperature
  دمای ِ ویریال   
damâ-ye viriyâl

Fr.: température du viriel   

The mean temperature at which a gravitationally → bound system would satisfy the → virial theorem. For a system of mass M and radius R with constant density, the gravitational energy per unit mass is W = GM/R. The kinetic energy per unit mass is E = (3/2)kTvir, where k is → Boltzmann's constant and μ the mean molecular weight. According to the virial theorem, E = W/2, which leads to the virial temperature Tvir = (1/3)(GM/kR).

virial; → temperature.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>