interstellar dust grain
dâne-ye qobâr-e andaraxtari
Fr.: grain de poussière interstellaire
→ dust grain.
Fr.: extinction interstellaire
The dimming of light traveling in the interstellar space due to the combined effects of absorption and scattering by interstellar dust particles. Interstellar extinction increases at shorter (bluer) wavelengths, resulting in → interstellar reddening.
Fr.: gaz interstellaire
Gas, mostly hydrogen, in the interstellar space found in a variety of forms: molecular, atomic, ionized, plasma.
Fr.: grain interstellaire
Fr.: raie interstellaire
A spectral line formed in the interstellar medium, in particular an absorption line which does not participate in the periodic Doppler shift of intrinsic absorption lines in a binary star.
interstellar magnetic field
meydân-e meqnâtisi-ye andaraxtari
Fr.: champ magnétique interstellaire
A large-scale, weak magnetic field, with an estimated strength of about 1 to 5 microgauss, that pervades the disk of the Milky Way Galaxy and controls the alignment of interstellar dust grains.
Fr.: maser interstellaire
A maser phenomenon created by young stars and → protostars in the surrounding dense → molecular clouds of gas and dust. See also → circumstellar maser; → ammonia maser; → methanol maser; → OH maser; → water maser.
Fr.: matière interstellaire
The gas and dust that exists in open space between the stars. See also → interstellar medium.
interstellar medium (ISM)
Fr.: milieu interstellaire
The environment containing the → interstellar matter, consisting of gas (mostly hydrogen) and dust. Even at its densest phase, the interstellar medium is emptier than the best vacuum man can create in the laboratory, but because space is so vast, the interstellar medium still adds up to a huge amount of mass.
Fr.: molécule interstellaire
Any molecule that occurs naturally in clouds of gas and dust in the interstellar medium. So far more than 140 species have been discovered, many of which nonexistent on Earth.
interstellar object (ISO)
Fr.: objet interstellaire
A body other than a → star or → substellar object located in → interstellar space and not → gravitationally bound to a star. Its → hyperbolic orbit would indicate an object not bound to the Sun. The first known ISO is → 1I/'Oumuamua. ISOs are icy → planetesimals that are expected to behave like the → long-period comets of the solar system; volatile ices sublimate when the ISO approaches the Sun, developing a → coma and a → dust tail -- features that should make them bright and therefore easy to spot. The rocky ISOs, on the other hand, only reflect sunlight. As their → albedo is expected to be extremely low they become dark (after eons of bombardment by high-energy cosmic rays), they would be extremely faint and hard to detect (Hainaut et al., 2018, The Messenger 173, 13).
Fr.: polarisation interstellaire
interstellar radiation field
meydân-e tâbeš andaraxtari
Fr.: champ de rayonnement interstellaire
A global ionizing radiation in the → interstellar medium provided by various sources all together.
Fr.: rougissement interstellaire
The dimming of light during its travel in the → interstellar medium due to absorption by → intervening → dust grains. Since shorter wavelengths are particularly affected, the spectrum of the light is increasingly dominated by the long wavelength end of the spectrum. As a result, the light is "reddened" as it travels through space. Robert J. Trumpler (1886-1956), a Swiss-American astronomer, was the first to produce a definite evidence of the existence of → interstellar extinction and to estimate its magnitude (1930).
interstellar reddening curve
xam-e sorxeš-e andaraxtari
Fr.: courbe de rougissement interstellaire
A graph showing the relation between → interstellar absorption (in magnitudes) and wavelength.
Fr.: scintillation interstellaire
An apparent twinkling of the signals from distant point-like radio sources (pulsars). It is due to turbulence, i.e. fluctuations in the electron density of the interstellar ionized gas, through which the signals have passed on their way to Earth.
1) A minute gap between the adjacent parts of a body or
objects close together.
Fr.: atom interstitiel
In a → crystal, an imperfection caused by the presence of an extra atom that occupies a place outside the normal → lattice position. It may be the same type of atom as the others (self interstitial) or an → impurity atom.
A network of fluid-filled spaces in the body's connective tissues all over the body. It lies below the skin's surface and surrounds arteries, muscles, and the digestive and urinary tracts in a layer long thought to be dense connective tissue. Interstitium could be the largest organ in the human body
From L. interstitium, → interstice.
Andarjâyân, from andarjâ, → interstice, + euphonic sound -y-, + relation suffix -ân.