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: 13176 Search : in
barium star
  ستاره‌ی ِ باریومی   
setâre-ye bâriyomi

Fr.: étoile à barium   

A type of star, usually G or K → giants, whose spectra show unusually strong absorption lines of → barium, → strontium, and other → s-process elements.

barium; → star.

bark
  کالون   
kâlun

Fr.: écorce   

The external covering on the trunks, boughs, and branches of trees.

M.E., from O.Norse börkr "bark."

Kâlun, from Mâzandarâni kâlun "bark," variants (Dâmqân) kul "bark," (Tâti) lo "bark," (Yazd, Mâzandarân) kol "bark," (Nâin) kuluz "egg shell," (Aftar) cokola "egg shell, pistaschio shell," pukel, → shell, keler, → scalp, probably related to (Khotan Sacca) karastra- "fur garment," (Waxi) kurust "bark of tree," from PIE root *(s)ker- "to cut off," from which are derived L. cortex "bark," corium "thick skin," scortum "hide," and Persian carm "leather."

Barlow lens
  عدسیِ بارلو   
adasi-ye Barlow (#)

Fr.: lentille de Barlow   

A → negative lens placed in a telescope between the → objective and the → ocular. Its diverging action reduces the convergence of the light cone, forming a larger image at a slightly greater distance.

Peter Barlow (1776-1862), English physicist; → lens.

barn
  بارن   
bârn (#)

Fr.: barn   

In nuclear physics, unit of area for measuring the cross-sections of nuclei. 1 barn equals 10-24 sq. cm.

Barn, from O.E. bereærn "barn," lit. "barley house," from bere "barley" + aern "house." The use of barn in nuclear physics comes from the fact that the term denotes also "an unexpectedly large quantity of something." It seems that when physicists were first studying nuclear interactions, they found out that the interaction probabilities, or cross-sections, were far more larger than expected; the nuclei were `as big as a barn'.

Barnard
  بارنارد   
Bârnârd

Fr.: Barnard   

From Edward Emerson Barnard (1857-1923) American astronomer who made several obserational discoveries.

Barnard's loop
  گردال ِ بارنارد   
gerdâl-e Bârnârd

Fr.: boucle de Barnard   

A very faint nebular shell of huge size enveloping the central portion of Orion.

Named after → Barnard, who discovered the loop in 1895; → loop.

Barnard's star
  ستاره‌ی ِ بارنارد   
setâre-ye Bârnârd

Fr.: étoile de Barnard   

A → red dwarf in the constellation → Ophiuchus discovered in 1916 by E.E. Barnard, that until 1968 had the largest → proper motion of any star. It moves on the sky 10.3 arcseconds per year, which means that it travels the equivalent of a lunar diameter every 180 years. It is the second nearest star system to the Sun.

In honor of → Barnard; → star.

baro-
  فشار-   
fešâr- (#)

Fr.: baro-   

A prefix meaning → pressure used in the formation of compound words, such as → baroclinic, → barometer, → barotropic.

Baro- combining form of Gk. baros "weight;" cognate with Pers. bâr "weight," gerân "heavy;" cf. Skt. guru, L. gravis; PIE *gwere- "heavy;" L. brutus "heavy, dull, stupid, brutish;" Skt. bhara- "burden, load," bharati "he carries;" PIE *bher- "carry, give birth."

Fešâr-, → pressure.

baroclinic
  فشارشیبی   
fešâršibi

Fr.: barocline   

Of, pertaining to, or characterized by → baroclinicity. Sometimes called → barocline.

baro-; → -cline; → -ic.

baroclinic instability
  ناپایداری ِ فشارشیبی   
nâpâydâri-ye fešâršibi

Fr.: instabilité barocline   

1) A type of instability occurring within a rapidly → rotating star where non-axisymmetric motions can separate surfaces of constant pressure from → equipotential surfaces.
2) A hydrodynamic instability associated with a baroclinic layer of the atmosphere. It arises from temperature variation along the pressure surfaces. Baroclinic instability is associated with the vertical → shear of the mean flow, which is related to the horizontal temperature gradient by the thermal wind equation. Instabilities in a baroclinic region grow by converting potential energy associated with the mean horizontal temperature gradient into kinetic energy through ascending warm air and descending cold air (Rasmussen & Turner (eds.), Polar Lows, Cambridge Univ. Press, 2003).

baroclinic; → instability.

baroclinicity
  فشارشیبی   
fešâršibi

Fr.: baroclinie   

The state of stratification in a fluid in which surfaces of constant pressure do not coincide with those of constant density, but intersect. Where baroclinicity is zero, the fluid is → barotropic. Same as baroclinity.

baroclinic; → -ity.

barometer
  فشارسنج   
fešârsanj (#)

Fr.: baromètre   

Instrument for measuring the atmospheric pressure. It is used in determining height above sea level and predicting changes in weather.

baro- + → -meter.

barometric law
  قانون ِ فشارسنجی، ~ فشارسنجیک   
qânun-e fešârsanji, ~ fešârsanjik

Fr.: loi barométrique   

A law which describes the vertical pressure distribution in the lower parts of Earth's atmosphere. The atmospheric pressure decreases exponentially from any reference surface as the altitude increases.

barometer; → law.

barotropic
  فشارگرد   
fešârgard

Fr.: barotrope   

In a fluid, conditions where surfaces of constant pressure are parallel to surfaces of constant temperature. This state is equivalent to zero → baroclinicity.

baro-; → -tropic.

barotropic gas
  گاز ِ فشارگرد   
gâz-e fešârgard

Fr.: gaz barotrope   

A gas whose density is a function solely of pressure.

barotropic; → gas.

barotropic instability
  ناپایداری ِ فشارگرد   
nâpâydâri-ye fešârgard

Fr.: instabilité barotrope   

A hydrodynamical instability that arises when the horizontal → shear gradient becomes very large. Barotropic instabilities grow by extracting kinetic energy from the mean flow field.

barotropic; → instability.

barotropy
  فشارگردی   
fešârgardi

Fr.: barotropie   

A state of a fluid in which the surfaces of constant density coincide with surfaces of constant pressure (isobaric).

barotropic gas.

barred
  میله‌دار، میله‌ای   
miledâr, milei

Fr.: barré   

Having a bar like structure.

bar.

barred Magellanic spiral
  مارپیچ ِ میله‌دار ِ ماژلانی   
mârpic-e mile-dâr-e Mâželâni

Fr.: spirtale barée magellanique   

A transitional class of object between the classic spiral galaxies and true irregular systems. The → Large Magellanic Cloud, the nearest and best studied example of the class, is, contrary to popular opinion, not an irregular galaxy. The LMC and other members of the SBm class have definite structural signatures. They are generally dominated by a pronounced asymmetric bar -- one that is offset from the optical center of the galaxy -- with a nascent spiral arm emanating from one end. As is the case with irregular galaxies, the optical centers of SBm type systems are not particularly special places. Disk systems later than Sc characteristically lack a central stellar concentration in addition to having weak spiral structure; this is true of SBm-type galaxies. SBm galaxies are typically very active in their star formation activity, often containing a large star-forming complex situated at one end of the bar. Beyond these general trends there is a tremendous amount of dispersion in physical properties within the SBm class, particularly in the strength of the spiral structure. At one extreme are the "one-armed" spirals such as NGC 3664 and NGC 4027 which are dominated by single, looping spiral arm. On the other hand NGC 4861 shows little evidence of spiral structure and it is dominated by a large star-forming complex at one end of its bar. The class smoothly leads to the Barred Magellanic irregulars (IBm) which show no indication of spiral structure (Wilcots et al. 1996, AJ 111, 1575).

Magellanic; → spiral; → galaxy.

barred spiral galaxy
  کهکشان ِ مارپیچ ِ میله‌دار، ~ ~ میله‌ای   
kahkašân-e mârpic-e miledâr

Fr.: galaxie spirale barrée   

A → spiral galaxy that exhibits a bar-shaped structure in its nucleus. → galactic bar.

barred; → spiral; → galaxy.

<< < -es -it -sc 201 951 abe abs abs aca acc acc aco act ada adh ado aer aft air Alf alg alk alp Alt alt amb ana And ang ani ann ant ant ant apo app app Apu arc arg Arn art ass ast ast ast atm ato att aur aut avo azi bac bal bar bar bat Bea Bel bet bia big bin bio Bir bla bla blo Blu bol Boo bou box bre Bri bro bur cal cal Can cap car Car cat cau cel cen cen cha Cha cha che Chi chr cir cir civ cla clo clo CMB 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 coo cor cor cor Cos cos cos cou cou cra cri cro cry cul cur cyc D l dar dat day dea dec dec dec def def deg Del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra Dsc dus dwa dyn Dys Ear ecc eco edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ eru eth Eur eve exa exc exe exi exo exp ext ext ext fab fai Fan fea fem fer fie fil fir fir fla fli flu foc for for for fra fre fre fri fun fuz gal gal gal Gam gau Gau gen geo geo geo geo Gib glo gov gra gra gra gra gre gro Gui H-a hal Ham har Hay hea hei hel Hel her het hie hig hoa hom hor hot Hub Hug hur hyd hyd hyl 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 inv ion iro Isl iso iso Jab jet Jov Jup Kar Kep kil Kip Kra Lag Lam Lan Lar las law lea Leg Leo lev lig lim lin lin lin lit loc loc log Lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal map mas mas mat Mau mea mea med Men mer Mes Met met mic mic Mie mil min Mir mix mod mol mom Moo mor mov mul mur n-b nan nat nea neg Ner neu new New NGC noc nom non non nor nor nuc nuc nul nut obj obl obs occ oct off old one ope opp opt opt orb ord org Ori osc oth ove Owl P-s Pal par par par par Pas pat pec pen per per per per per Pha pha pho pho pho phy pie pix Pla pla pla pla Pli Poi pol pol pol pol por pos pos pow pre pre pre pre pri pri pri pro pro pro pro pro pro pro pub pul pyc qua qua qua qua qui rad rad rad rad rad rad rai 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 rur S5- Sal sat sca sca Sch sci Scu sec sec sed sel sel sem seq set sha she sho sid sie sil sim sin sit sky slo sno sod sol sol sol sol son sou spa spa spe spe spe spe sph spi spo squ sta sta sta sta ste ste ste Sti sto str str sub sub sub sul sup sup sup sup sur sur syl syn sys tal Tay tel ten ter tex the the the the Tho thr tid tim Tit too Tor tra tra Tra tra Tra tri Tri tru tub tur two Typ ult ult unc uni uni uni upl ura uti val var vec vel ver Ver vie vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>