An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1026
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.

  ۱) تپیدن؛ ۲) تپ، تپش   
1) tapidan (#); 2) tap, tapeš (#)

Fr.: 1) battre, vibrer, pulser; 2) impulsion   

1a) (v.) To → beat, to → vibrate.
1b) (v.) Physics: To → emit  → particles or → radiation  → periodically in short → bursts.
2a) (n.) Physics: A variation of a quantity whose value is normally constant. The essential characteristics of a pulse are: a → rise, a finite → duration, and a → decay.
2b) (n.) Physics: A single, abrupt emission of particles or radiation. See also → pulse counter, → pulse nulling, → pulse width, → pulsed laser, → precursor pulse.

M.E., from M.Fr. pous, from L. pulsus "a beat," p.p. of pellere "to push, drive," from PIE *pel- "to shake, swing."

Tapidan "to beat, throb," Mid.Pers. tapīdan "to be anguished; to suffer; to grow hot, to be hot," variant tâftan, tâpidan "to stir up, to excite; to shine;" tâp "fever;" Av. tap- "to be hot, to grow hot," tafnah-, tafnu- "fever, feverish heat;" cf. Skt. tap- "to spoil, injure, damage,; to suffer; to give out heat, to be hot," tápati; L. tepere "to be warm;" PIE base *tep- "warm."

pulse counter
  شمارگر ِ تپ   
šomârgar-e tap

Fr.: compteur d'impulsion   

A device that records counts the total number of pulses received over a given time interval.

pulse; → counter.

pulse nulling
  نولش ِ تپ   
nuleš-e tap

Fr.: arrêt de pulsation   

A phenomenon seen in the → radio  → emission of many → pulsars where the emission appears to cease, or is greatly diminished, for a certain number of pulse periods. Typical time scales of nulling are of the order of a few pulse periods, however it may last for up to many hours in certain pulsars. For example, PSR B0826-34 is active for only about 20% of the time. Same as → pulsar nulling.

pulse + verbal noun of → null.

pulse width
  پهنای ِ تپ   
pahnâ-ye tap

Fr.: largeur de pulsation   

The interval of time between two successive pulses. Also called pulse length, pulse duration.

pulse; → width.

pulsed laser
  لیزر ِ تپی   
leyzer-e tapi

Fr.: laser pulsé   

A laser that emits short pulses of coherent light in fixed intervals, rather than a continuous flow of photons. → laser; → high power laser.

Pulsed adj. of → pulse; → laser.


Fr.: pomper   

To raise, drive, supply or inject as if by using a pump.

From M.E. pumpe, from M.Du. pompe "water conduit, pipe," or M.L.G. pumpe "pump."

Pompidan infinitive, from pomp, loan from Fr. pompe


Fr.: pompage   

The act or process of pumping. → optical pumping.

Verbal noun of → pump.

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.


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.


žâvi (#)

Fr.: pureté   

The degree to which → impurity is incorporated into a semiconductor material.

M.E., from O.Fr. pureté, from L.L. puritatem (nom. puritas) "cleanness, pureness," from purus "clean;" cf. Av. pūitika- "serving for purification," Mod.Pers. pâk "clean;" Skt. pavi- "to become clean," pávate "purifies, cleanses;" O.H.G. fouwen, fewen "to sift;" PIE base *peu- "to purify, cleanse."

Žâvi, noun from adj. žâv "pure."

Purkinje effect
  ا ُسکر ِ پورکین‌ی   
oskar-e Purkinje

Fr.: effect Purkinje   

The increasing sensibility of the retina for light of shorter wavelength as the brightness decreases. In those conditions red objects are perceived to fade faster than blue objects of the same brightness.

Named after the Czech anatomist Jan Evangelista Purkynne (1787-1869), who discovered the effect; → effect.


Fr.: but, objet   

The reason for which something exists or is done, made, used, etc. (

M.E. purpos, from O.Fr. porpos "aim, intention," from porposer "to put forth," from por- "forth," from L. → pro- "forth;" + O.Fr. poser "to put, place," → position.

Farneh, literally "put forth," from far-, variant of farâ-, → pro-, + neh present stem of nehâdan "to pose, place, lay," → position.


Fr.: résolu, déterminé   

Having a purpose; determined; resolute.

purpose + -ful a suffix meaning "full of," "characterized by."

Farnehmand, from farneh, → purpose, + -mand, → -al.


Fr.: exprès   

1) Intentionally; deliberately.
2) With the particular purpose specified; expressly (

purpose; → -ly.

cistân (#)

Fr.: énigme   

1) A problem that cannot be easily or readily solved.
2) A game, question, or problem designed for testing ingenuity.

Of unknown origin.

Cistân from cist "what is?," + -ân noun suffix.

pycnonuclear reaction
  واژیرش ِ چگال‌هسته‌ای   
vâžireš-e cagâl-hasteyi

Fr.: réaction pycnonucléaire   

A nuclear reaction that takes place at high densities and relatively low temperatures. Pycnonuclear reactions are almost temperature independent and occur even at zero temperature. These reactions are extremely slow at densities typical for normal stars but intensify with increasing density. For example, carbon burns into heavier elements at densities over 1010 g cm-3.

Pycnonuclear, from pycno- a combining form meaning "dense, thick," from Gk. pyknos "dense, solid" + → nuclear; → reaction.

Vâžireš, → reaction; cagâl-hasteyi, from cagâl, → dense, + hasteyi, → nuclear.


Fr.: pyrhéliomètre   

General term for the class of → actinometers that measure the intensity of solar radiation received on the surface of the Earth. It functions by converting the heat of the sunlight into a voltage using a device called a thermopile, and a recording voltmeter.

From pyr-, from → pyro- + → heliometer.

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