Asthenosphere, from Gk. asthenes "weak" + → sphere.
Sostsepehr, from sost "weak, tender" + sepehr, → sphere.
A photographic instrument with great light gathering power which is used to photograph a large field in a single exposure.
Fr.: physique des astroparicules
axtar-šidnegâri, šidnegâri-ye axtari
The photography of stars, other celestial bodies, and stellar fields.
axtar-šidsanji, šidsanji-ye axtari
The measurement of the intensity of light of celestial bodies.
Of or pertaining to → astrophysics.
Fr.: jet astrophysique
A very fast moving, → collimated beam of → ionized gas at high temperatures associated with most classes of compact objects that spin and/or accrete matter from their surroundings, such as → protostars, → X-ray binary systems, and, at a larger scale, with → active galactic nuclei, → gamma-ray bursts, and → quasars. In general, jet sources host → accretion disks and are associated with → magnetic fields. Astrophysical jets, despite their different physical scales and power, are morphologically very similar, suggesting a common physical origin. For example, in one extreme, → active galactic nuclei jets have typical sizes ≥ 106 pc, velocities near that of light c, and parent sources (→ massive black holes) with masses 106-9  Msun and luminosities ~ 1043-48Lsun; while in the other extreme, → young stellar objects jets have typical sizes ≤ 1 pc, velocities ≤ 10-3 c, and emerge from low mass protostars with masses ~ 1 Msun and luminosities (0.1-2 × 104) Lsun. Jets play an important → feedback role in the evolution of their host systems. See also: → jet launching.
Fr.: objet astrophysique
A scientist who studies → astrophysics.
The branch of → astronomy that deals with the → physics of → celestial objects and the → Universe in general. It relies on the assumption that the → laws of physics apply everywhere in the Universe and throughout all time. See also → observational astrophysics, → theoretical astrophysics.
Astrophysics, from → astro- "star" + → physics. The first use of the term astrophysics has been attributed to Johann Karl Friedrich Zöllner (1834-1882) in 1865. He defined it as a coalescence of physics and chemistry with astronomy (History of Astronomy: An Encyclopedia, ed. John Lankford, Routledge, 1997).
bonpâr-e atmodust, ~ havâdust, ~ goazdust
Fr.: élément atmophile
In the → Goldschmidt classification, a → chemical element that is extremely → volatile, i.e., forms a gas or liquid at the surface of the Earth. The atmophile elements are usually concentrated in the terrestrial → atmosphere and → hydrosphere. They are → hydrogen (H), → carbon (C), → nitrogen (N), and → noble gas/qot>es, namely → helium (He), → neion (Ne), → argon (Ar), → krypton (Kr), → xenon (Xe), and → radon (Rn) (Pinti D.L., 2017, Atmophile Elements. In: White W. (eds) Encyclopedia of Geochemistry, Springer).
javv (#), havâsepehr
1) The gaseous envelope surrounding a star, planet, or moon.
Several solar system planets
retain considerable atmospheres, due to their strong
gravitational force. The gas motions in the planetary
atmosphere, as a response to the heating, coupled with the rotation
forces, generate the meteorological systems. The planetary satellites
→ Titan and → Triton
also have atmospheres (M.S.: SDE).
New L. atmosphaera, from Gk. atmos "vapor" + spharia "sphere."
javvi, havâsepehri (#)
Pertaining to or existing in the atmosphere of an astronomical object such as a planet, moon, or star.
Fr.: absorption atmosphérique
The absorption of → electromagnetic radiation in the → atmosphere mainly by → water vapor, → carbon dioxide, and oxygen. The atmosphere introduces two more limiting factors in → remote sensing: → atmospheric scattering and → atmospheric turbulence.
Fr.: circulation atmosphérique
The large-scale movements of air around areas of high and low pressure whereby heat is distributed on the surface of the Earth. Atmospheric motion is driven by uneven heating of the planet. The atmosphere (and ocean) → transfers the excess heat from → tropics to → poles. The flow is determined by balance between → pressure gradients and the → Coriolis effect.
Fr.: dispersion atmosphérique
The splitting of starlight into a spectrum in the atmosphere because the atmosphere acts as a refracting prism. This phenomenon brings about a practical problem for spectroscopic observations using a slit. → differential refraction; → atmospheric refraction.
Fr.: émission atmosphérique
The emission of electromagnetic radiation from the atmosphere due to thermal and → non-thermal processes. → Thermal emission comes mainly from → water vapor. Non-thermal processes result in emission lines oxygen (optical) and OH (near-IR). Atmospheric emission is a very significant source of noise in astronomical observations. See also → airglow, → aurora.
Fr.: échappement atmosphérique
A process by which a planet loses its atmospheric gases to space. There are three main types: 1) → thermal escape, 2) → suprathermal escape (or → nonthermal escape), and 3) → impact erosion. According to models, the two mechanisms that can most efficiently cause substantial atmospheric loss are hydrodynamic escape and impact erosion (see, e.g., Catling, D. C. and Kasting, J. F., 2017, Escape of Atmospheres to Space, pp. 129-167. Cambridge University Press).
Fr.: extinction atmosphérique
The decrease in the intensity of light from a celestial body due to absorption and scattering by Earth's atmosphere. It increases from the zenith to the horizon and affects short wavelengths more than long wavelengths, so that objects near the horizon appear redder than they do at the zenith.