A lunar → impact crater that is located in the southern part of the Moon's near side. Latitude: 41.0°S, longitude: 0.2°E, diameter: 52 km, depth: 3.35 km.
Named after the Iranian mathematician and astronomer Nasireddin Tusi (1201-1274), → Nasireddin couple.
Fr.: couple de Nasireddin
A theorem put forward by the 13th century Persian mathematician and astronomer Nasireddin Tusi to generate linear motion from a combination of circular motions, and thus improve the geocentric model of Ptolemy. A circle of radius R rotates inside a circle of radius 2R. The smaller circle rotates at twice the speed of the larger one and in opposite direction. The initial tangent point will travel in linear motion back and forth along the diameter of the larger circle. A particular case of → hypocycloid curves.
Named for Nasireddin Tusi (1201-1274), director of Marâgha observatory who created the Ilkhani zij; → couple.
forusorx-e nazdik (#)
Fr.: proche infrarouge
That region of the → electromagnetic spectrum covering shorter infrared wavelengths. It contains the → infrared windows between about 0.8 and 8 → microns, but the longer wavelength limit is not well defined. See also: → infrared radiation, → mid-infrared, → far-infrared, → submillimeter radiation.
North Polar Layered Deposits (NPLD)
Lerdhâ-ye Laye-laye-ye Qotb-e Hudar
Fr.: couches de dépôt du pôle nord
A large area of the north polar region of Mars which is covered with alternating layers of water ice and dust. → South Polar Layered Deposits.
Fr.: réduction enligne
Preliminary reduction of observational data at a telescope simultaneously with their acquisition.
→ order + -ed.
Fr.: arbre ordonné
1) Act of plundering or robbing; predatory behavior.
Verbal noun, → prey.
Zoology: Any organism that exists by preying upon other organisms (Dictionary.com).
Agent noun from → prey.
1) Of, or relating to a predator.
Agent noun from → prey.
1) farâsan; 2) farâsandan
1a) Grammar: The part of a → sentence or
→ clause stating something about
the → subject and usually consisting of a
→ verb. For example, in
the sentence "The man opened the door," the subject is "the man" and the
predicate is "opened the door."
M.E., from M.Fr. predicat, from L. praedicatus "declared, proclaimed," p.p. of praedicare, from prae "beforehand," → pre-, + dicare "proclame," from stem of dicere "to speak, to say," from PIE root *deik- "to point out, to show," cognate with Pers. dis, → form, and andišidan, → think.
guyik-e farâsani, ~ farâsanhâ
Fr.: logique des prédicats
Fr.: symbole de prédicat
That part of the electromagnetic spectrum, with a wavelength between 610 and 780 nm, that produces the impression of a variety of colors resembling that of blood.
M.E. red, from O.E. read (cf. Dan. rød, M.Du. root, Ger. rot), from PIE base *reudh- (cf. Av. raoidita- "red, reddish;" Skt. rudhirá- "red, bloody;" L. ruber "red;" Gk. erythros "red").
Sorx "red" (variants Tâleši sər, Kurd. sûr), from Mid.Pers. suxr "red;" O.Pers. θuxra-; Av. suxra- "red, of fire-color;" Ossetic syrx, surx "red;" cf. Skt. śukrá- "clear, pure, bright."
Fr.: grumeau rouge
A concentration, on the → horizontal branch, of → red giant stars that roughly have the same intrinsic brightness. These core → helium burning stars are the metal rich equivalents of the better known → horizontal branch stars. Theoretical models predict that their absolute luminosity only weakly depends on their age and chemical composition.
red clump star
setâre-ye gude-ye sorx
Fr.: étoile du grumeau rouge
kutule-ye sorx (#)
Fr.: naine rouge
A small, cool, very faint, main sequence star whose surface temperature is under about 3500 K. Red dwarfs generally have masses of less than one-third that of the Sun. In the neighbourhood of the Sun the majority of stars are red dwarfs.
qul-e sorx (#), qulpeykar-e ~ (#)
Fr.: géante rouge
A certain star of spectral type K or later that occupies the upper right portion of the → H-R diagram. Red giants are evolved stars that have exhausted their hydrogen fuel in the core. They may have a → luminosity up to 1000 times greater than → main sequence stars of the same → spectral type. Red giants belong to the → luminosity class III or II (bright giants). They are luminous because of their great size, but have a relatively low surface temperature. All normal stars are expected to pass eventually through a red-giant phase as a consequence of stellar evolution. When a main sequence star has converted approximately 10% of its hydrogen to helium, nuclear reactions in the core stop (→ Schönberg-Chandrasekhar limit). The → hydrostatic equilibrium is no longer maintained, and the core contracts while the outer layers expand and cool. This process produces the low surface temperature and large size (from 10 to 100 times that of the Sun) that characterize the red giant. In the core the temperature continues to rise. When it approaches 100,000,000 K helium will begin to fuse into carbon. → helium flash. Prominent bright red giants in the night sky include → Aldebaran and → Arcturus.
red giant branch (RGB)
šâxe-ye qulân-e sorx
Fr.: branche des géantes rouges
red HB star
Fr.: étoile RHB
Same as → red horizontal branch star.