hierarchical triple system
râžmân-e bastâyi-ye nâpâygâni
Fr.: système multiple non hiérarchique
A triple star system in which the (inner) binary is orbited by a third body in a much wider orbit. → hierarchical multiple system.
setâye-ye Pythagoras, ~ Fisâqures
Fr.: triplet de Phythagore
M.E., from M.L. triplare "to triple," from L. triplus "threefold, triple," from tri-, → three, + -plus "-fold."
Setâyi, from setâ, from sé→ three + tâ "fold, plait, ply; piece, part," Mid.Pers. tâg "piece, part."
triple alpha process
farâravand-e âlfâ-ye setâyi
Fr.: réaction triple alpha
A chain of nuclear fusion reactions by which three helium nuclei (→ alpha particles) are transformed into → carbon. First two nuclei of helium collide, fuse, and form a nucleus of → beryllium: 4He + 4He ↔ 8Be, which is unstable and will decay back into two helium nuclei within a few 10-17 seconds. However, due to sufficiently high density and temperature in the stellar core, during a third collision between beryllium and helium, carbon is formed: 8Be + 4He → 12C + γ. The triple-alpha process is possible owing to the existence of the → Hoyle state. It is the main source of energy production in → red giants and → red supergiants in which the core temperature has reached at least 100 million K. Also called → Salpeter process.
Fr.: conjonction triple
A rare event involving a particularly intricate set of movements of two planets or a planet and a star where they meet each other three times in a short period either in opposition or at the time of inferior conjunction, if an inferior planet is involved. The visible movement of the planet or the planets in the sky is therefore normally prograde at the first conjunction, retrograde at the second conjunction and again prograde at the third conjunction.
noqte-ye segâné (#)
Fr.: point triple
The definite pressure and temperature at which all three phases of a substance coexist in → phase equilibrium. The triple point of water has a pressure of 4.58 mm of Hg and a temperature of 273.16 °K.
Fr.: étoile triple
A group of three stars visually or physically associated with each other. → triple system.
Fr.: système triple
A system of three stars which are physically associated among them.
A group or set of three of one kind.
Setâyé, from setâ, → triple, + -(y)é nuance suffix.
Fr.: état triplet
The electronic state of an atom or molecule which has two unpaired electrons, and therefore whose total spin angular momentum is equal to 1.