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: 466 Search : pH
orbitography
  مدارنگاری   
madârnegâri

Fr.: orbitographie   

In astronautics, the study of satellite orbits and precise determination of orbital elements which gives the exact position of the satellite.

orbital + → -graphy.

order of a graph
  رایه‌ی ِ نگاره   
râye-ye negâré

Fr.: ordre de graphe   

The → number of → vertices.

order; → graph.

orphan
  یتیم   
yatim (#)

Fr.: orphelin   

1) A child who has lost both parents through death, or, less commonly, one parent.
2) A young animal that has been deserted by or has lost its mother (Dictionary.com). → orphaned protostar.

M.E., from L.L. orphanus "destitute, without parents," from Gk. orphanos "bereaved;" akin to L. orbus "bereaved," Skt. arbhah "weak, child," Armenian orb "orphan," O.Irish orbe "heir," O.C.S. rabu "slave," Ger. Erbe, O.E. ierfa "heir," O.H.G. arabeit, Ger. Arbeit "work," O.E. earfoδ "hardship, suffering, trouble."

Yatim "fatherless," from Ar.

orphaned protostar
  پوروا-ستاره‌ی ِ یتیم   
purvâ-setâre-ye yatim

Fr.: proto-étoile orpheline   

A → protostellar object which has been dynamically ejected from a newborn → multiple star system, either into a tenuously bound orbit or into an escape, thus depriving it from gaining much additional mass. Recent observations have shown that → Class I protostellar sources have a population of distant companions at separations ~ 1000 to 5000 → astronomical unit (AU)s. Moreover, the companion fraction diminishes as the sources evolve. According to N-body simulations of unstable → triple systems embedded in dense cloud cores, many companions are ejected into unbound orbits and quickly escape, but others are ejected with insufficient momentum to climb out of the potential well of the cloud core and associated binary. These loosely bound companions reach distances of many thousands of AU before falling back and eventually being ejected into escapes as the cloud cores gradually disappear (B. Reipurth et al. 2010, arXiv:1010.3307).

orphan; → protostar.

osculating sphere
  سپهرِ آبوسنده، کره‌یِ آبوسنده   
sepehr-e âbusandé, kore-ye ~

Fr.: sphère osculatrice   

For a curve C at a point p, the limiting sphere obtained by taking the sphere that passes through p and three other points on C and then letting these three points approach p independently along C.

osculating; → sphere.

out of phase
  نافاز، ناهم‌فاز   
nâfâz, nâ-ham-fâz

Fr.: déphasé   

The condition of two oscillators that have the same frequency but different phases. Opposed to → in phase.

out; → phase.

particle physics
  فیزیک ِ ذره‌ای   
fizik-e zarreyi (#)

Fr.: physique des particules   

The branch of physics that deals with the smallest known structures of matter and energy in order to understand the fundamental particles and forces of nature.

particle; → physics.

Pasiphae
  پسیفاءه   
Pâsifâé

Fr.: Pasiphaé   

The fifteenth of Jupiter's known satellites, orbiting at 23,660,000 km from Jupiter; also known as Jupiter VIII. Its diameter is 36 km and orbital period 744 days.

In Gk. mythology, Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur.

peripheral
  پیرابَری   
pirâbari

Fr.: périphérique   

Pertaining to, situated in, or constituting the periphery.

Adj. of → periphery.

peripheral response
  پاسخ ِ پیرابَری   
pâsox-e pirâbari

Fr.: réponse périphérique   

In a charge-coupled device, the detection of charge collected by the transport register rather than by the image-sensing elements.

peripheral; → response.

peripheral vision
  دید ِ پیرابَری   
did-e pirâbari

Fr.: vision périphérique   

In optics, the ability to see over large angles of view.

peripheral; → vision.

periphery
  پیرابَر   
pirâbar

Fr.: périphérie   

The external surface or boundary of a body. The circumference or perimeter of any closed figure.

From, M.E., from O.Fr. periferie, from L.L. peripheria, from Gk. peripheria "circumference, outer surface," literally "a carrying around," from peripheres "rounded, moving round," peripherein "to carry or move round," from → peri- "round about" + pherein "to carry;" cognate with Pers. bordan "to carry, lead," as below.

Pirâbar, from pirâ-, → peri-, + bar present stem of bordan "to carry, lead" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry").

pH
  پ-هاش، پی-اچ   
p-hâš, pi-ec

Fr.: potentiel hydrogène   

A → logarithmic measure of → hydrogen ion concentration, originally defined pH = log10 (1/[H+]), where [H+] is the concentration of hydrogen ions in → moles per liter of solution. The hydrogen ion concentration in pure water around room temperature is about 1.0 × 10-7 moles. Therefore, a pH of 7 is considered "neutral," because the concentration of hydrogen ions is exactly equal to the concentration of → hydroxide (OH-) ions produced by → dissociation of the → water. Increasing the concentration of hydrogen ions above 1.0 × 10-7 moles produces a solution with a pH of less than 7, and the solution is considered → acidic. Decreasing the concentration below 1.0 × 10-7 moles produces a solution with a pH above 7, and the solution is considered → alkaline or → basic. The neutral pH is different for each → solvent. For example, the concentration of hydrogen ions in pure ethanol is about 1.58 × 10-10 moles, so ethanol is neutral at pH 9.8. A solution with a pH of 8 would be considered acidic in ethanol, but basic in water.

From Ger. PH, introduced by Danish biochemist S.P.L. Sørensen (1868-1939) in 1909, from P, for Ger. Potenz "power, potency," and H, symbol of → hydrogen.

Phad (γ UMa)
  فخذ   
Faxez (#)

Fr.: Phecda   

A blue, → main sequence star of → apparent visual magnitude 2.44 and → spectral type A0 Ve located in → Ursa Major. Other designations: Phecda; Phekda; Phegda; Phekha; Phacd.

Phad, from Ar. al-Fakhidh (ad-Dubb) (الفخذ‌الدب) "the thigh (of the Bear)".

Faxez, from Ar., as above.

Phaeton
  فایتون   
Phaeton

Fr.: Phaéton   

A hypothetical → planet which once was postulated to have existed between the orbits of → Mars and → Jupiter and its destruction supposedly led to the formation of the → asteroid belt. The idea of such a hypothetical planet was first put forward by the German astronomer Heinrich Wilhelm Olbers (1758-1840).

In Greek mythology Phaeton was the sun god Helios. Phaeton tried to drive his father's solar chariot but crashed after almost setting fire to the whole earth.

pharynx
  حلق   
halq (#)

Fr.: pharynx   

The tube or cavity, with its surrounding membrane and muscles, that connects the mouth and nasal passages with the esophagus (Dictionary.com). → throat.

From Gk pharynx (genitive pharyngos) "windpipe, throat."

Halq, loan from Ar.

phase
  ۱، ۲) فاز؛ ۳) سیما   
1, 2) fâz; 3) simâ

Fr.: phase   

1) A particular stage or point in a course, development, or graph varying cyclically; the fractional part of the period through which the time has advanced, measured from some arbitrary origin. Phase is measured like an angle, when a complete cycle is equivalent to a phase of 360° (or 2π radians), or, sometimes, as a number between 0 and 1. Two or more waves of the same frequency are → in phase when their maxima and minima take place at the same moments. Otherwise, they are said to be → out of phase or that they have a → phase difference.
2) A state in which matter can exist, depending on temperature and pressure, e.g. the → solid, → liquid, → gaseous, and → plasma states.
3) A recurring form of the → Moon or a → planet seen in the sky. → lunar phase, → phases of Venus.
4) In a → binary star system, → orbital phase.

Mod.L. phases, plural of phasis, from Gk. phasis "appearance," from stem of phainein "to show, to make appear."

1) Fâz, loanword from Fr., as above.
2) Simâ "face, aspect, resemblance."

phase angle
  زاویه‌ی ِ فاز   
zâviye-ye fâz (#)

Fr.: angle de phase   

1) Physics: Of a → periodic wave, the number of suitable units of angular measure between a point on the wave and a reference point.
2) Astro.: For an object in the solar system, the angle "Sun-object-Earth" that is, the angle between the Sun and the observer as seen from the given object. It is 0° when the object is fully illuminated, 90° when the object is half-illuminated (like the Moon at first quarter and last quarter), and 180° when the object is between Earth and the Sun.
3) More generally, the angle between star light incident onto a related revolving object and the light reflected from the object to the observer (Earth).

phase; → angle.

phase curve
  خم ِ فاز   
xam-e fâz

Fr.: courbe de phase   

1) Astro.: A curve describing the → brightness of a reflecting → natural satellite as a function of its → phase angle.
2) Math.: A plot of the solution to a set of equations of motion in a phase space as a function of time.

phase; → curve.

phase delay
  درنگ ِ فاز   
derang-e fâz

Fr.: délai de phase   

The ratio of the phase shift of a sinusoidal signal in transmission through a system to the frequency of the signal.

phase; → delay.

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