# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 174 Search : line
 linear velocity   تندای ِ خطی   tondâ-ye xattiFr.: vitesse linéaire   The rate of change of the position of an object that is traveling along a straight path. In other words, the velocity of an object when its moving direction is not changing. For a given → angular velocity (ω), the linear velocity v of the particle is directly proportional to the distance of the particle from the center of the circular path: v = ω ×r.→ linear; → velocity. linearity   خطیگی   xattigiFr.: linéarité   The property, condition, or state of being linear. Math.: A relationship between two variables so that when plotted on a graph they yield a straight line.→ linear; → -ity. linearization   خطش، خطانش   xatteš, xattânešFr.: linéarisation   A process of reduction to linear form by appropriate change of variables or by approximation.Verbal noun of → linearize. linearize   خطیدن، خطانیدن   xattidan, xattânidanFr.: linéariser   To make linear; give linear form to.→ linear + → -ize. linearized differential equation   هموگش ِ دگرسانه‌ای ِ خطی   hamugeš-e degarsâneyi-ye xattiFr.: équation différentielle linéarisée   A differential equation that has been derived from an original nonlinear equation.Linearized, p.p. of → linearize; → differential; → equation. linearly   خطانه   xattânéFr.: linéairement   In a manner characterized by first-degree algebraic terms.Adverb of → linear. linearly dependent   خطانه وابسته   xattâné vâbastéFr.: linéairement dépendant   A set of objects x1, x2, ..., xn (→ vectors, → matrices, → polynomials, etc.) on a given set if there is a linear combination of them: a1x1 + a2x2 + ... + anxn, which is zero, but at least one of the coefficients is non-zero. For example the binomials (2x + y) and (6x + 3y) are linearly dependent, since 3(2x + y) - (6x + 3y) = 0.→ linearly; → dependent. linearly independent   خطانه ناوابسته   xattâné nâvâbastéFr.: linéairement indépendant   1) A set of objects x1, x2, ..., xn (→ vectors, → matrices, → polynomials, etc.) if it si not → linearly dependent. 2) Of two particular solutions (y1, y2) of a → homogeneous linear differential equation of the second order (y'' + a1 y' + a2y = 0) on an interval [a, b], if their ratio in this interval is not a constant: y1/y2≠ constant.→ linearly; → independent. linearly polarized light   نور ِ قطبیده‌ی ِ خطی   nur-e qotbide-ye xattiFr.: lumière polarisée linéairement   Light exhibiting → linear polarization.→ linearly; → polarized; → light. LINER   لاینر   lâyner (#)Fr.: LINER   A type of galactic nucleus that is defined by its spectral line emission. The lines are very weak, the most prominent ones being from low ionization states (such as [O II], [N II], [S II] and [OI]). There is so far no generally accepted interpretation of the spectra of liners. It is likely that galaxies of different histories may have their nuclei with liner-type spectra. → retired galaxy.Short for → Low-Ionization Nuclear Emission-line Region. The term liner was first introduced by T. M. Heckman (1980, A&A 87, 152). linewidth   خط-پهنا، پهنای ِ خط   xatt-pahnâ (#), pahnâ-ye xatt (#)Fr.: largeur de raie   1) The range of frequencies or wavelengths over which radiations are absorbed or emitted in a transition between a specific pair of atomic energy levels. The full width is determined between half-power points of the line. 2) In a laser, the range of frequencies over which most of the beam energy is distributed.→ line; → width. lithium I line   خط ِ لیتیوم I   xatt-e litiom IFr.: raie de lithium I   A → resonance line of → lithium at 6707.81 Å doublet 6707.76 and 6707.91 Å.→ lithium; I for → neutral atom; → line. low-ionization line   خط ِ کم‌یونش   xatt-e kamyoneš (#)Fr.: raie de faible ionisation   A spectral line arising from a transition between atomic levels with an ionization potential below approximately 15 electron-volts.→ low; → ionization; → line. low-ionization nuclear emission-line region   ناحیه‌ی ِ هسته‌ای با خط ِ گسیلی ِ کم‌یونش   nâhiye-ye hasteyi bâ xatt-e gosili-ye kamyoneš (#)Fr.: Noyau de galaxie à raies d'émission de faible ionisation   Same as → LINER.→ low; → ionization; → nuclear; → emission; → line; → region. Lyman alpha line   خط ِ لایمن-آلفا، تان ِ ~ ~   xatt-e Lyman-âlfâ (#), tân-e ~ ~Fr.: raie Lyman alpha   The spectral line in the → Lyman series which is associated with the → atomic transition between → energy levels n = 2 and n = 1. The corresponding wavelength is 1216 Å in the → far ultraviolet.→ Lyman; → line. magnetic field line   خط ِ میدان ِ مغناتیسی   xatt-e meydân-e meqnâtisi (#)Fr.: ligne de champ magnétique   An imaginary line used for representing the strength and direction of a magnetic field. Charged particles move freely along magnetic field lines, but are inhibited by the magnetic force from moving across field lines.→ magnetic; → field; → line. masculine   نرین   narin (#)Fr.: masculin   1) Having qualities appropriate to or usually associated with a man. 2) Of, relating to, or constituting the gender that ordinarily includes most words or grammatical forms referring to males (Merriam-Webster.com).M.E. masculin, from O.Fr. masculin "of the male sex," from L. masculinus "male, of masculine gender," from masculus "male, masculine; worthy of a man," diminutive of mas "male person, male," of unknown origin.Narin, from nar, → male. Na I D-line   خط ِ D ی ِ Na I   xatt-e D-ye Na IFr.: raie D de Na I   → D line.Na, → sodium; → D line. narrow-line region   ناحیه‌ی ِ باریک-خط   nâhiye-ye bârik-xattFr.: région à raies étroites   The outer region of a → quasar or an → active galactic nucleus displaying narrow spectral lines. Also called Type II AGN. See also → obscuring torus.→ narrow; → line; → region. natural line broadening   پهنش ِ زاستاری ِ خط   pahneš-e zâstâri-ye xattFr.: élargissement naturel de raie   The broadening of any spectral line due to the fact that excited levels have mean lives, which, by virtue of the uncertainty principle, implies a spread in the energy values.→ natural; → line; → broadening.