Fr.: objet abstrait
An entity that does not exist in space or time and is not perceptible. Some examples are universals, sets, geometrical figures, and numbers.
barâxt-e anâm, ~ binâm
Fr.: objet anonyme
An → astronomical object which has not been catalogued.
barâxt-e axtaršenâsik, ~ axtari
Fr.: objet astronomique
A naturally occurring physical entity or association that lies beyond the Earth's atmosphere and can be studied observationally. In other words, a gravitationally bound structure that is associated with a position in space, but may consist of multiple independent astronomical objects. A list of astronomical objects includes → planets, → asteroids, → comets, → stars, → nebulae, galaxies (→ galaxy), → galaxy clusters, → pulsars, and → black holes. Note that → celestial body, → celestial object, and → heavenly body are less technical terms for these entities.
Fr.: objet astrophysique
Fr.: objet de Becklin-Neugebauer
A compact infrared source in the Orion molecular cloud (OMC-1). It is thought to be a very dusty compact H II region surrounding a young B0 or B1 star.
After Eric Becklin (1940-), and Gerry Neugebauer (1932-) who discovered the object in 1967; → object.
BL Lac object
barâxt-e BL Calpâsé
Fr.: objet BL Lac
A member of a family of → quasars, or extragalactic → Active Galactic Nuclei, which displays a high radio emission and/or important optical variability over a short period of time. BL Lac objects appear star-like but their spectrum is flat, and partially polarized. Also called → blazars.
BL Lac, from object BL in the constellation → Lacerta (BL Lacertae). The reason for this terminology is that it was originally thought to be an irregular variable star in our Galaxy; hence its variable star designation. In the 1970s the "star" was identified with a bright, variable → radio source and a very faint galaxy; → object.
Fr.: objet céleste
compact central object (CCO)
barâxt-e hampak-e markazi
Fr.: objet compact central
An → X-ray source detected close to the center of young → supernova remnant (SNR)s that has no apparent emission in other wave-bands and no binary companions. Although these sources have been known and studied for several decades without much understanding of their nature, exciting results over the past few years have brought them into the forefront of → neutron star studies. They have soft, exclusively thermal spectra in the few hundred eV range and X-ray luminosities around 1033 - 1034 erg s-1. About ten CCOs are presently known, including the central sources of CasA, Puppis A and Kes 79 supernova remnants. Several, J1852+0040 in Kes79, J0822.0-4300 in Puppis A and 1E 1207.4-5209 in PKS 1209-51/52, have detected pulsations in the hundreds of milliseconds range. J1852+0040 has a detected → period derivative, indicating that it is spinning down like a → rotation-powered pulsar (RPP). The measured period and either measurements or constraints on period derivative indicate that these sources have very low → magnetic fields in the range 1010 - 1011 G assuming magnetic dipole braking. Since their SNRs are all young, ~ 103 - 104 yr, they were probably born with unusually low magnetic fields, which makes them "anti-magnetars" (A. K. Harding, 2013, Front. Phys. 8, 679 and references therein).
Fr.: objet compact
Fr.: objet éruptif
Fr.: objet étendu
An object whose angular size exceeds the resolution of the instrument used to observe it.
Fr.: objet de champ
An astronomical object that is seen in the direction of a group but not physically belonging to the group. → field galaxy.
Fr.: objets flottants
A population of → substellar objects which are not bound to stars; they are detected in young star clusters. Their masses, estimated from their fluxes, is several Jupiter masses, lower than those of → brown dwarfs. Their formation is not yet explained. Among the envisaged possibilities: 1) These objects form like stars, from protostellar core collapse and subsequent accretion; 2) they form as low-mass members of small groups, and are ejected from the group; 3) they form like planets within circumstellar disks of higher-mass objects, but are ejected either due to internal dynamics or external interactions.
Barâxt, → object; šenâvar "that swims, floats," from šenâ "swimming;" Mid.Pers. šnâz "swim," šnâzidan "to swim;" Av. snā- "to wash, swim;" cf. Skt. snā- "to bathe, to wash;" L. nare, natare "to swim" (Fr. nage, nager, natation; Sp.nadar, natacion).
FU Orionis object
barâxt-e FU Šekârgar
Fr.: objet FU Orionis
A member of a class of → pre-main sequence stars that experience dramatic changes in magnitude and → spectral type. During an outburst the luminosity of such an object can increase by several orders of magnitude on short time-scales (few months to few years). The phenomenon is explained by abrupt mass transfer from an → accretion disk to a young, low mass → T Tauri star (accretion rates 10-4 to 10-3 solar masses per year). → EX Lupi; → Z CMa.
Fr.: objets Herbig-Haro
A small patch of → nebulosity in a → star-forming region, created when fast-moving → jets of material (with speeds up to about 1000 km per sec) from a newborn star collide with the → interstellar medium.
high redshift object
Fr.: objet à grand décalage vers le rouge
A galaxy or quasar having a → redshift larger than about 0.8, corresponding to a → look-back time half the present age of the Universe. The qualifier "high" is, however, relative and depends on context and authors' assessment.
inner Earth object (IEO)
barâxt-e daruni-ye madâr-e zamin
Fr.: objet interne à l'orbite terrestre
Kuiper belt object (KBO)
barâxt-e kamarband-e Kuiper
Fr.: objet de la ceinture de Kuiper
Fr.: objet amplificateur
barâxt-e mazdâhik, ~ riyâzi
Fr.: objet mathématique
An → abstract object dealt with in mathematics that has a definition, obeys certain properties, and can be the target of certain operations. It is often built out of other, already defined objects. Some examples are → numbers, → functions, → triangles, martices (→ matrix), → groups, and entities such as → vector spaces, and → infinite series.