Fr.: élargissement de raie
A widening of → spectral lines due to any of several factors, including the → Doppler broadening, → instrumental broadening, → microturbulence, → pressure broadening, → rotational broadening, the → Stark effect, and the → Zeeman effect.
Fr.: refroidissement dû aux raies
In stellar atmosphere models, the decrease of temperature in the outer layers of atmosphere due to the escape of photons through optically thin metallic lines. Energy is transferred from the thermal pool to photons and is lost for the atmosphere, leading to a temperature decrease.
Fr.: identification de raies
The process of recognizing the spectral lines in a spectrum.
Fr.: intensité de raie
A measure of the total effect of an absorption or emission line. The line intensity is equal to the integration of the absorption coefficient over the entire shape of the absorption line.
line of action
xatt-e žireš, ~ koneš
Fr.: ligne d'action
Of a force, the straight line along which the force → vector is directed. The action of a force on a → rigid body does not change when its point of application is displaced along the line of action. Hence, forces applied to a rigid body can be regarded as non-localized, or sliding, vectors.
line of apsides
Fr.: ligne des apsides
line of equinoxes
Fr.: ligne des équinoxes
The intersection of the planes of ecliptic and celestial equator.
line of flow
Fr.: ligne d'écoulement
Same as → streamline.
line of force
khatt-e niru (#)
Fr.: ligne de force
One of many → imaginary lines whose direction at all → points along its length is that of the electric or → magnetic field at those points. In → electric fields the lines of force are directed toward → negative charges and point away from → positive charges. In magnetic fields the lines of force are directed from the → north pole to the → south pole.
line of induction
Fr.: ligne d'induction
Same as → line of force in a magnetic field.
line of nodes
xatt-e gerehhâ (#)
Fr.: lignes des nœuds
The line created by the intersection of the equatorial plane and the orbital plane.
line of sight
xatt-e did, didxatt (#)
Fr.: ligne de visée
The imaginary straight line connecting the object and the objective lens of the viewing device.
Fr.: profil de raie
The representation of a spectral line as produced by an observing instrument.
line profile variability (LPV)
vartandegi-ye farâpâl-e xatt
Fr.: variabilité du profil de raie
binâb-e xatti (#)
Fr.: spectre de raies
Spectrum consisting of discrete lines (emission or absorption), each corresponding to a particular wavelength, as opposed to a continuous spectrum.
Fr.: intensité de raie
Same as → line intensity.
xatbâl, bâl-e xatt
Fr.: aile de raie
Part of the line profile between the continuum level and the half value of the emission or absorption peak. The wings are due to matter traveling at much greater speeds than that providing the main peak. → red wing; → blue wing.
A stellar atmosphere model which includes metals or uses methods to reproduce their effects, → line blanketing.
Fr.: vent induit par raie
Same as → radiation-driven wind.
Any of a countless number of dark streaks visible on → Europa's surface that crisscross the whole → Galilean satellite. They are up to 1,000 km long, 20 km wide, and 1 km deep, but only hundred of meters high. In many cases, the ridges are double, often with dark outer edges and a central band. Images show that on each side of the lines, the edges have moved relative to each other. According to the most likely hypothesis, lineae result from eruptions of warm water, in a scenario similar to the present day mid- oceanic ridges on Earth.
From L. linea, → line.
Xaš, → streak.