<< < -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 > >>
polar wind bâd-e qotbi Fr.: vent polaire 1) The → solar wind occurring at high latitudes during low
→ solar activity as a fast
(around 750 km s-1) and relatively
steady flow. A remarkable feature of the polar wind is the ubiquitous presence of
an intense flow of → Alfvénic fluctuations. |
polarimetric qotbešsanji, qotbešsanjik Fr.: polarimétrique Of or relating to → polarimetry. → polarimetry; → -ic. |
polarimetry qotbešsanji Fr.: polarimétrie The measurement of the → polarization state of light, usually through the use of a polarimeter. From polari, from → polarization + → -metry. |
Polaris setâre-ye qotbi, jodey, mix-e gâh Fr.: étoile polaire The brightest star associated with the → north celestial pole. Polaris, also called the Pole Star, is a → triple system lying at about 433 → light-years (133 → parsecs) from the Earth. It is not exactly located on the Earth → rotation axis, because an → angular distance of 42 degrees (about 1.4 lunar diameter) separates it from the true north pole. The main star, Polaris Aa (→ visual magnitude about 2), is a variable → pulsating star of type → Cepheid. It is a hot, blue F7 Ib → supergiant star having a → luminosity about 1,260 times that of the Sun. It has a mass of 5.4 Msun, a radius of 37.5 Rsun, and a → surface temperature of 6,015 K. The close companion Ab apparent magnitude 9.2) is only 0''.17 (about 18.5 → astronomical units) from Polaris A. It was discovered in 1929 through examining the spectrum of Polaris A. It orbits Aa every 29.59 years. Ab is a → main sequence star of → spectral type F6 V. It has a mass of 1.26 Msun, a radius of 1.04 Rsun, and a luminosity of 3 Lsun. The third component, Polaris B (visual magnitude 8.7), is separated from A by 18.2 arc sec, corresponding to approximately 2,400 AU. It was first noticed by William Herschel in 1780. Polaris B is a main sequence star of type F3 V with a mass 1.39 Msun, a radius 1.8 Rsun, a luminosity of 3.9 Lsun, and a surface temperature of 6,900 K. Due to the → precession of equinoxes, the direction that Earth's axis points at changes slowly with time. Hence, Polaris has not always been, nor will it always be, the Pole Star. Polaris is actually drawing closer to the pole and in 2100 it will be as close to it as it ever will come, just 27.15 arc-minutes or slightly less than the Moon's apparent diameter. It will continue its reign as the North Star for many centuries to come. Historically, around 400 B.C., during Plato's time the nearest star to the Pole star was → Kochab (β Ursae Minoris). Some 4,600 years ago, when the Egyptians constructed the Pyramids, the Pole star was → Thuban (α Draconis). In 2,000 years the star → Errai (γ Cephei) will become the Pole Star. And around the year 14,000, Earth's axis will point reasonably close to the star → Vega, the fifth brightest star in the sky. Mod.L. short for stella polaris "the pole star," → polar. Setâre-ye qotbi "polar star," from setâré,
→ star, + qotbi, → polar. |
polarity qotbigi Fr.: polarité 1) Physics: The condition, in a system, of having opposite characteristics at
different points, especially positive or negative with respect to electric charge or
magnetic properties. |
polarity epoch zime-ye qotbigi Fr.: époque de polarité The time during which the Earth's magnetic field was of a single polarity; an interval of time between reversals of Earth's magnetic field. |
polarity event ruydâd-e qotbigi Fr.: événement de polarité A specific event in the history of Earth's magnetic field. Usually used in reference to a specific → polarity reversal. |
polarity reversal v âruneš-e qotbigi, vâgardâni-ye ~ Fr.: inversion de polarité 1) A change in the → polarity of Earth's magnetic field
in which the north magnetic pole becomes the south magnetic pole and vice versa.
Also known as geomagnetic reversal or magnetic reversal. Earth's magnetic
field has reversed many times in the past and the time intervals
between these changes are known as → polarity epochs. |
polarizable qotbeš-pazir Fr.: polarisable Able to be polarized. |
polarization qotbeš (#) Fr.: polarisation 1) Optics: A process or state in which the directions of the electric or magnetic fields
of an → electromagnetic radiation
change in a regular pattern. Light can be polarized by a
variety of ways, involving the following processes: reflection, transmission,
double refraction, and scattering. See also
→ unpolarized light;
→ linear polarization;
→ circular polarization;
→ elliptical polarization.
The study of the polarization of light from astronomical sources can yield
unique information in particular related to the properties of magnetic fields. Verbal noun of → polarize. |
polarization angle zâviye-ye qotbeš (#) Fr.: angle de polarisation Same as → polarizing angle and → Brewster angle. → polarization; → angle. |
polarization charge bâr-e qotbeš Fr.: Same as → bound charge. → polarization; → charge. |
polarization degree daraje-ye qotbeš (#) Fr.: degré de polarisation → polarization; → degree. |
polarization fraction barxe-ye qotbeš Fr.: fraction de polarisation The ratio expressed by P = (Ipar - Iper) / (Ipar + Iper), where Ipar and Iper are the light intensities with the electric field vector respectively parallel and perpendicular to the incident beam. → polarization; → fraction. |
polarize qotbidan (#) Fr.: polariser To cause → polarization. To undergo polarization. Infinitive of → polarization. |
polarized qotbidé (#) Fr.: polarisé Of or pertaining to a medium or physical phenomenon that exhibits → polarization. P.p. of → polarize. |
polarized light nur-e qotbidé (#) Fr.: lumière polarisée → Electromagnetic radiation in the optical region which has undergone → polarization. |
polarizer qotbandé (#) Fr.: polariseur An optical device capable of transforming natural light into polarized light, usually by selective transmission of polarized rays. Agent noun of → polarize. |
polarizing angle zâviye-ye qotbeš (#) Fr.: angle de polarisation The angle of → incidence for which the reflected light is completely polarized. Also called the → Brewster angle and → polarization angle. See also → Brewster's law. |
polarizing filter pâlâye-ye qotbandé (#) Fr.: filtre polarisant A filter that polarizes light passing through it. |
<< < -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 > >>