Fr.: primaire, principal
M.E., from L. primarius "of the first rank, principal," from primus "first."
Naxostân, from naxost, from Mid.Pers. naxust "the first," Parthian Mid.Pers. nxwšt, from naxu, Manichean Parthian nwx "beginning" + -ist superlative suffix, Av. -išta-, cf. Skt. -istha-, Gk. -istos, O.H.G. -isto, -osto, O.E. -st, -est, -ost.
Fr.: corps principal
primary cosmic rays
partowhâ-ye keyhâni-ye naxostân
Fr.: rayons cosmiques primaires
The → cosmic rays which arrive on the Earth's → atmosphere from the outer space. The primary cosmic rays are very high energy → protons and to a lesser extent heavier nuclei which rain upon the Earth from all diretions in the outer space. They contain about 90% protons, 7% → alpha particles and about 1% still heavier nuclei of amost all the atoms from Li to Ni ( → mass number< 60). See also: → secondary cosmic rays.
Fr.: éclipse primaire
Of a transiting → exoplanet, the event and the interval of time during which the planet passes in front of its host star. The planet occults a portion of the stellar disk, and a fraction of light from the star is seen after traversal through the atmosphere around the planet's limb. → secondary eclipse.
Fr.: miroir primaire
Fr.: arc-en-ciel primaire
The main rainbow that forms between about 40° and 42° from the
→ antisolar point
(or about 50° from the → antisolar point),
as viewed by the observer. The light path involves
→ refraction and a → single
→ reflection inside the water
→ droplet. If the drops are large, 1
millimeter or more in diameter, red, green, and violet are bright but
there is little blue.
Fr.: étoile principale