An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 14 Search : pulse
AGB final thermal pulse (AFTP)
  تپه‌ی ِ گرمایی ِ پایانی ِ AGB   
tape-ye garmâyi-ye pâyâni-ye AGB

Fr.: flash de l'hélium final de l'AGB   

In evolutionary models of → low-mass and → intermediate-mass stars, the occurrence of a → helium shell flash just at the moment when the star is leaving the → asymptotic giant branch phase.

AGB; → final; → thermal; → pulse.



A situation in which two heavenly bodies apparently approach each other. A close → conjunction in which no → occultation actually occurs.

L. appulsus, from appellere, appulsum "to drive to," from ad, → ad- + pellere "to drive".

Hamtâxt from ham- "against; together" + tâxt, from tâxtan "to rush upon, run, assault".

tekâné (#)

Fr.: impulsion   

Of a force acting on a body, the → product of the → force and the → time for which it acts. If the force changes with time, the impulse is the → integral of the force with respect to the time during which the force acts, and is equal to the total change of → momentum produced by the force: ∫F dt = ∫m dv. Impulse is a → vector quantity.

From L. impulsus "a push against, pressure, shock," p.p. of impellere "to push, strike against, drive forward," from → in- "into" + pellere "to push, drive."

Tekâné, from tekân "involuntary motion, sudden shaking," related to tak "rush, quick motion, stroke, blow" (tâxtan, tâzidan "to run; to hasten; to assault"); Mid.Pers. tak "assault, attack;" Av. taka- "leap, run," from tak- "to run, flow;" cf. Skt. tak- "to rush, to hurry," takti "runs;" O.Ir. tech- "to flow;" Lith. teketi "to walk, to flow;" O.C.S. tešti "to walk, to hurry;" Tokharian B cake "river;" PIE base *tekw- "to run; to flow;" → flow.

impulse-momentum principle
  پروز ِ تکانه-جنباک   
parvaz-e tekâné-jonbâk

Fr.: principe impulsion-quantité de mouvement   

The vector → impulse of the → resultant force on a particle, in any time interval, is equal in magnitude and duration to the vector change in momentum of the particle: ∫F dt = mv2 - mv1. The impulse-momentum principle finds its chief application in connection with forces of short duration, such as those arising in collisions or explosions. Such forces are called → impulsive forces.

impulse; → momentum; → principle.

late thermal pulse
  تپه‌ی ِ گرمای ِ دیران   
tape-ye garmâyi-ye dirân

Fr.: flash de l'hélium tardif   

In evolutionary models of → low-mass and → intermediate-mass stars, the occurrence of a → helium shell flash on the → horizontal branch of the → post-AGB track, while → hydrogen shell burning is still going on.

late; → thermal; → pulse.

precursor pulse
  تپ ِ پیشگام   
tap-e pišgâm

Fr.: pulse précurseur   

A component of a → pulsar pulse that appears shortly in advance of the main pulse.

precursor; → 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.

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.

vâzadan (#)

Fr.: repousser   

To drive back; to repel.
repulsion, → repulsive force, → repulsive gravity.

M.E., from L. repulsus, p.p. of repellere, from → re- "back" + pellere "to drive, strike, push."

Vâzadan "to repulse," from vâ-re- + zadan "to strike, beat; to play an instrument; to do" (Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill").

thermal pulse
  تپه‌ی ِ گرمایی، تپش ِ ~   
tape-ye garmâyi, tapeš-e ~

Fr.: pulsation thermique   

Repeated instabilities of the He burning shell which ignites in sudden burst during the final phases of the → AGB evolution.

thermal; → pulse.

very late thermal pulse (VLTP)
  تپه‌ی ِ گرمای ِ بسیار دیر   
tape-ye garmâyi-ye besyâr dir

Fr.: flash de l'hélium très tardif   

In evolutionary models of → post-asymptotic giant branch stars, the occurrence of the helium shell burning when the star has reached the → white dwarf cooling track. This leads to the possibility of a violent → helium shell flash and expansion on a time-scale of ≤ 10 years. The rapid expansion and prompt change in surface composition observed in → Sakurai's Object are thought to be due to such a very late thermal pulse.

very; → late; → thermal; → pulse.