An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1001
publish
  واگاندن   
vâgândan

Fr.: publier   

To issue (printed or otherwise reproduced textual or graphic material, computer software, etc.) for sale or distribution to the public (Dictionary.com).

M.E. publisshen, O.Fr. publier "make public, spread out, communicate," from L. publicare "make public," from publicus, → public.

Vâgândan "to diffuse, scatter, disperse," on the model of parâgandan, parâkandan "scatter, disperse," from vâ- "asunder, apart, off, away," → dis-, + gân variant of gan, kan (cf. Av. vikān- "to destroy," Kurd. nikândin "to bury"), from Proto-Ir. *kan- "to throw, place, put," → scatter.

publisher
  واگانگر   
vâgângar

Fr.: éditeur   

A person or company whose business is the publishing of books, periodicals, engravings, computer software, etc. (Dictionary.com).

Agent noun from → publish; → -er.

pulsar
  پولسار، تپار   
pulsâr (#), tapâr (#)

Fr.: pulsar   

A rotating → neutron star that emits a radio → beam that is centered on the → magnetic axis of the neutron star. As the magnetic axis and hence the beam are inclined to the → rotation axis, a → pulse is seen every time the → rotation brings the → magnetic pole region of the neutron star into view. In this way the pulsar acts much as a light house does, sweeping a beam of radiation through space. The pulse or spin periods range from 1.4 milliseconds to 8.5 seconds. As neutron stars concentrate an average of 1.4 → solar masses on a diameter of only 20 km, pulsars are exceedingly → dense and → compact, representing the densest matter in the observable Universe. The pulsar radiation, chiefly emitted in → radio frequencies (0.1-1 GHz), is highly → polarized. The exact mechanism by which a pulsar radiates is still a matter of vigorous investigation. Simply put, an enormous electric field is induced by the rotation of a magnetized neutron star. The force of this field exceeds gravity by ten to twelve orders of magnitudes. Charged particles are whereby pulled out from the stellar surface resulting in a dense, magnetized plasma that surrounds the pulsar (→ magnetosphere). The charged particles flow out of the magnetic → polar caps of the neutron star, following the open magnetic field lines. The acceleration of the charged particles along the curved magnetic field lines will cause them to radiate (see, e.g., M. Kramer, 2010, astro-ph/1008.5032).
See also:
accreting neutron star, → anomalous X-ray pulsar, → binary pulsar, → black-widow pulsar, → Crab pulsar, → double pulsar, → Hulse-Taylor pulsar, → isolated neutron star (INS), → millisecond pulsar, → neutron star, → nulling fraction, → nulling pulsar, → optical pulsar, → pulsar glitch, → pulsar magnetosphere, → pulsar nulling, → pulsar planet, → pulsar wind nebula, → radio pulsar, → recycled pulsar, → rotation-powered pulsar (RPP), → Vela pulsar, → X-ray Dim Isolated Neutron Star (XDINS), → X-ray pulsar.

Pulsar, from puls(e) or puls(ing) + (st)ar.

Tapâr, from tap, → pulse, + (set)âr(é), from setâré, → star.

pulsar glitch
  گلس ِ پولسار، ~ تپار   
geles-e pulsâr, ~ tapâr

Fr.:   

A sudden change in the pulsar period due to a sudden shift in the crust of the → neutron star (a → starquake).

pulsar; → glitch.

pulsar magnetosphere
  مغنات‌سپهر ِ پولسار   
meqnâtsepehr-e pulsâr

Fr.: magnétosphère de pulsar   

A dense zone of magnetized → plasma surrounding a → pulsar. The magnetosphere, lying between the surface of the → neutron star and the → light cylinder, corotates with the pulsar like a rigid body under the effect of strong magnetic field. The magnetosphere's thickness is determined by the constraint that the corotation velocity of its upper surface should not exceed the → speed of light.

pilsar; → magnetosphere.

pulsar nulling
  نولش ِ پولسار   
nuleš-e pulsâr

Fr.: phase d'arrêt de pulsar   

A phenomenon in which the → pulsar  → emission abruptly drops to zero or near zero for a certain number of → pulse  → periods, then suddenly returns to normal. Nulling is relatively common in pulsars. The → nulling fraction can be more than 80%. Investigating the emission behaviors of → nulling pulsars is important to understand the pulsar emission mechanism.

pulsar; → null; → -ing.

pulsar planet
  سیاره‌ی ِ پولساری، تپار ِ ~   
sayyâre-ye pulsâri, tapaar-e ~

Fr.: planète de pulsar   

A planet orbiting a → pulsar. The first such planet to be discovered was around a → millisecond pulsar known as PSR 1257+12.

pulsar; → planet.

pulsar wind nebula (PWN)
  میغ ِ باد ِ پولسار، ~ ~ تپار   
miq-e bâd-e pulsâr, ~ ~ tapâr

Fr.: nébuleuse de vent de pulsar   

Same as → plerion.

pulsar; → wind; → nebula.

pulsate
  تپیدن   
tapidan (#)

Fr.: battre, palpiter   

To expand and contract rhythmically.

Verb from → pulse.

pulsating star
  ستاره‌ی ِ تپنده   
setâre-ye tapandé (#)

Fr.: étoile pulsante   

A type of → variable star that changes its brightness by changing its volume through expansion and contraction. Classical pulsating stars, including → Cepheids, → RR Lyrae, and → Delta Scuti variables, are located in a quite narrow almost vertical region in the → H-R diagram, known as → instability strip. See also → kappa mechanism.

Pulsating, verbal adj. of → pulsate; → star.

pulsating Universe
  گیتی ِ تپنده   
giti-ye tapandé

Fr.: Univers oscillatoire   

Same as → oscillating Universe.

Pulsating, verbal adj. of → pulsate; → universe.

pulsation
  تپش   
tapeš (#)

Fr.: pulsation   

The act of pulsating; beating or throbbing; vibration or undulation. → stellar pulsation.

Verbal noun of → pulse.

pulsation mode
  ترز ِ تپش، مُد ِ ~   
tarz-e tapeš, mod-e ~

Fr.: mode de pulsation   

The way in which pulsations occur in a star due to the fact that stars act as resonant cavities, as studied in → asteroseismology. A star may pulsate either with approximately spherical symmetry (radial pulsation), or as a series of waves running across the surface (non-radial pulsation). Pulsation may occur in a single mode or in multiple modes, depending on the type of star. Three different modes of pulsations have been detected through the → helioseismology of the → Sun: → p mode, → g mode, and → f mode, generated by acoustic, gravity, and surface gravity waves respectively. Also called → oscillation mode.

pulsation; → mode.

pulsational
  تپشی   
tapeši

Fr.: pulsationnel   

Of or pertaining to → pulsation. → pulsational instability; → pulsational pair-instability supernova.

pulsation; → -al

pulsational instability
  ناپایداری ِ تپشی   
nâpâydâri-ye tapeši

Fr.: instabilité pulsationnelle   

A term used to describe irregularly spaced, fine-scale structure in optically thick rings. The process relies on a combination of viscosity and self-gravity of ring material to produce this fine structure. Also known as overstability (Ellis et al., 2007, Planetary Ring Systems, Springer).

pulsational; → instability.

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.

pulse
  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.

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