An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 244 Search : up
pulsational pair-instability supernova
  اَبَر-نو‌اختر ِ ناپایداری ِ تپشی ِ جفت   
abar-now-axtar-e nâpâydâri-ye tapeši-ye joft

Fr.: supernova à instabilité pulsationnelle de paires   

A → supernova resulting from the → pair instability that generates several successive explosions. According to models, a first pulse ejects many solar masses of hydrogen layers as a shell. After the first explosion, the remaining core contracts and searches for a stable burning state. When the next explosion occurs a few years later, several solar masses of material are again ejected, which collide with the earlier ejecta. This collision can radiate 1050 erg of light, about a factor of ten more than an ordinary → core-collapse supernova. After each pulse, the remaining core contracts, radiates neutrinos and light, and searches again for a stable burning state. Later ejections have lower mass, but have higher energy. They quickly catch up with the first shell, where the collision dissipates most of their kinetic energy as radiation. The first SNe from → Population III stars are likely due to pulsational pair instability (Woosley et al. 2007, Nature 450, 390). See also → pair-instability supernova.

pulsational; → pair; → instability.

pupil
  مردمک   
mardomak (#)

Fr.: pupille   

1) In the → eye, the apparently black opening in the center of the → iris that permits light to pass and be focused on the → retina.
2) In a → lens, the → image of the → aperture stop as seen from → object and → image space. Same as → entrance pupil.

From M.E. pupille, from O.Fr. pupille, from L. pupilla, originally "little girl-doll," diminutive of pupa "girl, doll" (Fr. poupée), so called from the tiny image one sees of himself reflected in the eye of another.

Mardomak "little man," the allusion being to the tiny image of himself reflected in the eye of another, from mardom "man, human being, mankind, people;" → people, + diminutive suffix -ak.

pupil masking
  ماسک‌زد ِ مردمک   
mâskzad-e mardomak

Fr.: masquage de pupille   

A method for reaching the → diffraction-limited  → angular resolution of a monolithic telescope by using an → interferometric technique. A mask with several small openings is placed in the telescope pupil plane or in a conjugated plane so as to only pass light from selected regions, thus transforming the telescope into an array of small subapertures without redundancy. When the light from each of these separate subapertures is combined, → interference fringes are formed which encode information on the spatial structure of the source (Haniff et al. 1987, Nature 328, 694). Coupled with a novel technique which filters the → atmospheric turbulence through fibers, pupil masking allows reaching a high dynamic range (Perrin et al. 2006, MNRAS 373, 747), which is necessary for detecting very faint objects, such as → exoplanets, adjacent to bright stars.

pupil; → masking.

Puppis
  پسال   
Pasâl

Fr.: Poupe   

The Stern. One of the larger constellations of the southern hemisphere representing the stern of the ship Argo Navis, located at 7h 30m right ascension, 40° south declination. Its brightest star is → Naos. Abbreviation: Pup; genitive: Puppis.

From L. puppis "stern, poop, the rear, or aft part of a ship or boat."

Pasâl, from pas "behind" (e.g.: pas-e pardé "behind the curtain"), variant pošt "back; the back; behind" (Mid.Pers. pas "behind, before, after;" O.Pers. pasā "after;" Av. pasca "behind (of space); then, afterward (of time);" cf. Skt. paścā "behind, after, later;" L. post, as above; O.C.S. po "behind, after;" Lith. pas "at, by;" PIE *pos-, *posko-) + -âl, → -al. → prow = farâl (فرال).

Puppis A
  پسال A   
Pasâl A

Fr.: Puppis A   

A → supernova remnant in the constellation → Puppis, and one of the brightest sources in the X-ray sky. The → supernova occurred about 4000 years ago at a distance of about 6,000 light-years. Also called SNR G260.4-03.4. Its X-ray designation is 2U 0821-42.

Puppis.

quadruple
  چهارتا، چهارتایی   
cahârtâ (#), cahârtâyi (#)

Fr.: quadruple   

Fourfold; consisting of four parts.

M.E. from L. quadruplus, from quadru- + duple, from duplus, from du(o) "two" + -plus "fold."

Cahârtâ, from cahâr, → four, cognate with L. quattuor, + "fold, plait, ply; piece, part" (Mid.Pers. tâg "piece, part").

quadruple system
  راژمان ِ چهارتایی   
râžmân-e cahârtâyi

Fr.: système quadruple   

A stellar system consisting of four stars orbiting around a common → center of mass.

quadruple; → system.

quadrupolar
  چهارقطبه، چهارقطبه‌ای   
cahârqotbé (#), cahârqotbe-yi (#)

Fr.: quadrupolaire   

Of or pertaining to a → quadrupole, especially a → quadrupole moment.

quadrupole + -ar, → -al.

quadrupole
  چهارقطبه   
cahârqotbé (#)

Fr.: quadrupôle   

A set of either two → electric dipoles or two → magnetic dipoles in close proximity to each other arranged with alternating polarities and acting as a single unit. Quadrupole interactions are much smaller than dipole interactions, but can allow transitions forbidden in dipole moment transitions.

From L. quadru-, variant of quadri- "four" + → pole, on the model of → dipole.

Cahâr, → four, + qotb, → pole + noun/nuance suffix .

quadrupole anisotropy
  نا-ایزوگردی ِ چهارقطبه   
nâ-izogardi-ye cahârqotbé

Fr.: anisotropie quadrupolaire   

The → anisotropy which is at the origin of the → cosmic microwave background polarization. The quadrupole anisotropy could arise from three types of perturbations: → scalar perturbation, → vector perturbation, and → tensor perturbation

quadrupole; → anisotropy.

quadrupole lens
  عدسی ِ چهارقطبه   
adasi-ye cahârqotbé

Fr.: lentille quadrupôle   

A device, consisting of four → electrodes or → magnetic poles arranged in alternating → polarity, that focuses a beam of → charged particles.

quadrupole; → lens.

quadrupole moment
  گشتاور ِ چهارقطبه   
gaštâvar-e cahârqotbé

Fr.: moment quadrupolaire   

A quantity characterizing an electric charge distribution, determined by the product of the charge density, the second power of the distance from the origin, and a spherical harmonic over the charge distribution.

quadrupole; → moment.

Quintuplet cluster
  خوشه‌ی ِ پنجتایه   
xuše-ye panjtâyé

Fr.: amas du quintuplet   

A bright → open cluster of stars located within 100 light-years of the center of the Milky Way Galaxy, and one of the three → Galactic center clusters. The Quintuplet cluster was originally noted for its five very bright stars, but it is now known to contain many luminous → massive stars that are not detected at visible wavelengths due to heavy extinction by dust along the line of sight. The cluster is about 4 million years old and had an initial mass over 104 solar masses. The five brighter stars of the cluster are dusty → WC Wolf-Rayet stars. The Quintuplet cluster also contains two → Luminous Blue Variables, the Pistol star and FMM362. The Pistol star has a luminosity 107 times solar making it one of the most luminous stars known. The Quintuplet cluster is more dispersed than the nearby → Arches cluster.

Quintuplet, from the five brightest stars originally observed; → cluster.

red supergiant
  ابَرغول ِ سرخ   
abarqul-e sorx (#)

Fr.: supergéante rouge   

A supergiant star with spectral type K or M. Red supergiants are the largest stars in the Universe, but not necessarily the most massive. Betelgeuse and Antares are the best known examples of a red supergiant.

red; → supergiant.

rupture
  پارگی، گسست   
pâregi (#) , gosast (#)

Fr.: rupture   

Breaking apart or bursting. → plastic, → plasticity.

From L. ruptura "the breaking (of an arm or leg), fracture," from p.p. of rumpere "to break."

Pâregi "rupture," from pâré, → partial; gosast, → Big Rip.

Russell-Saunders coupling
  جفتش ِ راسل-ساندرز، جفسری ِ ~   
jofteš-e Russell-Saunders, jafsari-ye ~

Fr.: couplage Russell-Saunders   

A coupling scheme of → electron configuration, used mainly for the lighter atoms with → atomic number less than 30. In an atom when changes in energy states are produced by the action of two or more electrons, the value of the total angular momentum of these electrons results from the coupling between the total → orbital angular momenta of the electrons and the total → spin angular momenta of the electrons. In this scheme the orbital angular momenta and spin angular momenta of electrons are added separately to give the total angular momentum L = Σi li and the total electron spin angular momentum S = Σi si. These are then added to give J = L + S. Also called → LS coupling. See also → jj coupling.

After Henry Norris Russell (1877-1957) and Frederick Albert Saunders (1875-1963), American astronomers (1925, ApJ 61, 38); → coupling.

scale up
  فراز-مرپلیدن   
farâz-marpelidan

Fr.:   

In computer science, to increase the processing power of the same node/system by increasing its resources (CPU, RAM, etc.). This is a type of → vertical scaling opposite to → scale down. For example, instead of a machine with a CPU running at speed of X and having Y gigabytes of memory, use a machine with a CPU running at speed of 4X and a memory of 4Y gigabytes. See also → scale in, → scale out.

scale; → up.

Sculptor Group
  گروه ِ پیکرتراش   
goruh-e Peykartarâš

Fr.: groupe du Sculpteur   

The nearest group of galaxies to our → Local Group, lying near the south Galactic pole at about 10 million → light-years distance. The Sculptor Group is dominated by five galaxies, four spiral (NGC 247, 253, 300, and 7793) and one irregular (NGC 55). The brightest of the five is NGC 253. The nearest galaxy in this group is NGC 55 which at a distance of 5 million light-years lies on the border of the Local Group.

Sculptor; → group.

second dredge-up
  برونکشید ِ دوم   
borunkašid-e dovom

Fr.: deuxième dragage   

A → dredge-up process that occurs after core helium burning, in which the convective envelope penetrates much more deeply, pushing hydrogen burning shell into close proximity with the helium burning shell (→ first dredge-up). This arrangement is unstable and leads to burning pulses. The reason is that the hydrogen shell burns out until there is enough helium for the helium combustion to occur and all the helium is rapidly burnt. Afterward the hydrogen shell again burns outward and the process repeats.

second; → dredge-up.

sextuplet
  ششتایی   
šeštâyi

Fr.: sextuplet   

A group or combination of six objects, such as the → Mizar and the → Castor star systems.

From sextuple, from L. sext(us) "sixth," → six, + et

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