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: 403
Orion association
  آهزشِ شکارگر، ~ اُریون   
âhazeš-e Šekârgar, ~ Orion

Fr.: association d'Orion   

A large OB stellar association centered on the → Orion Nebula. Lying some 1500 → light-years away, it is about 400 light-years across and contains the main stars of Orion, except → Betelgeuse.

Orion; → association.

Orion Bar
  میله‌ی ِ شکارگر، ~ اوریون   
mile-ye Šekârgar, ~ Orion

Fr.: barre d'Orion   

A part of a → molecular cloud toward the → Orion Nebula viewed edge-on. It is the surface of interaction between the → H II region and its → associated molecular cloud. Same as the → Orion Bright Bar.

Orion; → bar.

Orion Bridge
  پل ِ شکارگر   
pol-e šekârgar

Fr.: pont d'Orion   

Same as → Orion Arm.

Orion; → bridge.

Orion Bright Bar
  میله‌ی ِ درخشان ِ شکارگر، ~ ~ اُریون   
mile-ye deraxšân-e Šekârgar, ~ ~ Orion

Fr.: barre brillante d'Orion   

A prominent emission ridge in the → Orion Nebula located approximately 2' southeast of the → Trapezium cluster. Various observations have suggested that it is an escarpment in the main → ionization front of the Nebula seen almost edge-on. The Orion Bar is one of the nearest and best-studied → photodissociation regions.

Orion; → bright; → bar.

Orion correlation theory
  نگره‌ی ِ هم‌باز‌آنش ِ اوریون   
negare-ye hambâzâneš-e Oryon

Fr.: théorie de la corrélation d'Orion   

A controversial proposition according to which a coincidence would exist between the mutual positions of the three stars of → Orion's Belt and those of the main Giza pyramids. More specifically, Khufu, Khafre, and Menkaure would be the monumental representation of → Alnitak, → Alnilam, and → Mintaka, respectively.

Orion; → correlation; → theory.

Orion molecular cloud
  ابرِ مولکولی ِ شکارگر، ~ ~ ا ُریون   
abr-e molekuli-ye Šekârgar, ~ ~ Orion

Fr.: nuage moléculaire d'Orion   

A giant cloud, or complex of clouds, of interstellar gas and dust associated with the Orion nebula (M42). It is about 1,500 light-years away and measures about 240 light-years across. Besides M42 and M43 it contains a number of famous objects, including Barnard's Loop, the Horsehead Nebula, and the reflection nebulae around M78. Within this cloud, stars have formed recently, and are still in the process of formation.

Orion; → molecular cloud.

Orion Nebula
  میغِ شکارگر، ~ ِ ا ُریون   
miq-e Šekârgar, ~ Oryon

Fr.: Nébuleuse d'Orion   

The best known → ionized nebula and one of the nearest regions to the Sun in which stars are presently being formed. It is visible to the naked eye in the constellation → Orion south of → Orion's Belt as a fuzzy patch. It lies about 1,500 → light-years away and measures about 30 light-years across. The Orion Nebula is ionized and made visible by a small group of → O-type and → B-type stars known as the → Trapezium cluster. Other designations: M 42, NGC 1976. See also: → Orion molecular cloud; → Huygens Region ; → Orion association; → Orion Bar; → Orion Bright Bar.

Orion; → nebula.

Orion OB1 Association
  آهزش ِ OB1 شکارگر، ~ ~ اریون   
âhazeš-e OB1 Šekârgar, ~ ~ Oryon

Fr.: Association Orion OB1   

An → OB association consisting of several dozen → hot stars of → spectral types O and B (→ O star, → B star). The Orion OB1 association consists of several subgroups, first divided by Blaauw (1964) into four subgroups. The subgroups differ in age and gas and dust content:
Orin OB1a, which contains the stars to the northwest of → Orion's Belt stars. Within this group lies another subgroup, known as the → 25 Orionis group;
Orion OB1b, containing the group of stars located in and around the Belt;
Orion OB1c, including the stars around → Orion's Sword; and
Orion OB1d, which contains the stars in and close to the → Orion Nebula (including the → Trapezium cluster).

Orion; → OB association.

Orion Spur
  شخاک ِ شکارگر   
šaxâk-e šekârgar

Fr.: éperon d'Orion   

Same as → Orion Arm.

Orion; → → spur.

Orion's Belt
  کمربندِ شکارگر، ~ اُریون   
kamarband-e Šekârgar, ~ Orion

Fr.: Ceinture d'Orion   

Three prominent stars in the central regions of the constellation → Orion that align to form the "belt" of the mythological Hunter. They are → Alnitak (ζ Ori), → Alnilam (ε Ori), and → Mintaka (δ Ori). The easternmost star Alnitak is separated from the middle one, Alnilam, by 1°.36, and the westernmost Mintaka has an angular distance of 1°.23 from Alnilam. Their distance is between 800 and 1,300 → light-years from Earth. They probably formed inside the same → molecular cloud less than 10 million years ago.

Orion; → belt.

Orion's Sword
  شمشیر ِ شکارگر، ~ اریون   
Šamšir-e Šekârgar, ~ Oryon

Fr.: Epée d'Orion   

An astronomical → asterism in the constellation → Orion forming an almost vertical line beneath → Orion's Belt. From north to south, the most prominent objects in the Sword are the cluster NGC 1981, the star → 42 Orionis, the famous → Orion Nebula, and the Sword's brightest star → Iota Orionis (→ Hatsya). None of these objects is particularly bright in itself, but their proximity to one another and the nebulosity across much of this region makes the Sword stand out clearly in the night sky.

Orion; → sword.

Orion-Cygnus Arm
  بازوی ِ شکارگر-ماکیان   
bâzu-ye šekârgar-mâkiyân

Fr.: bras Orion-Cygne   

Same as → Orion Arm.

Orion; → Cygnus; → arm.

Orionids
  شکارگریان   
Šekârgariyân

Fr.: orionides   

A meteor shower that appears to emanate from the constellation → Orion. It peaks between October 14 and 20 with about 20 meteors per hour.

Orion + → -ides.

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.

orrery
  اُرِری   
oreri

Fr.: planétaire   

A mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in heliocentric model.

Named after Charles Boyle, 4th Earl of Orrery (1676-1731), for whom the device was first made.

ortho-
  اردا-   
ardâ-

Fr.: ortho-   

Prefix denoting right, straight, correct.
Prefix indicating that an organic compound contains a benzene ring substituted in the 1.2 position.

Ortho-, from Gk. orthos "set upright, straight, true, correct, regular;" cf. L. arduus "high, steep," O.Ir. ard "high;" also cognate with Av. ərəduua-, as below; from PIE *eredh- "high."

Ardâ-, from Av. ərəduua- "upright, erect, risen;" cf. Skt. ūrdhvá- "upright, tending upward, high;" Gk. ortho, as above.

ortho-water
  اردا-آب   
adrdâ-âb

Fr.: eau ortho   

The → water molecule in which the → nuclear spin of the constituent → hydrogen atoms are → parallel (→ orthohydrogen). In astrophysics the ratio between ortho- and → para-water is used to determine temperatures in → interstellar medium.

ortho-; → water.

orthocenter
  اردامرکز   
ardâmarkaz

Fr.: orthocentre   

Of a triangle, the point where the three → altitudes of the → triangle converge.

ortho-; → center.

orthogonal
  ارداکنج   
ardâkonj

Fr.: orthogonal   

In elementary geometry, pertaining to or involving right angles or perpendiculars.
Of a system of real functions, defined so that the integral of the product of any two different functions is zero.
Of a linear transformation, defined so that the length of a vector under the transformation equals the length of the original vector.
Of a square matrix, defined so that its product with its transpose results in the identity matrix.

ortho- + gonia "angle," related to gony "knee;" L. genu "knee;" Mod.Pers. zânu "knee;" Av. žnav-, žnu- "knee;" Skt. janu-; PIE base *g(e)neu-, see below, + → -al

Ardâkonj, from ardâ-, → ortho-, + konj "angle, corner, confined place" (variants xong "corner, angle," Tabari kânj, Kurd. kunj, Hamadâni kom), maybe from the PIE base *g(e)neu-, as above, and related to Mod.Pers. zânu "knee" (Av. žnu-), Skt. kona- "angle, corner," Gk. gony, gonia, L. cuneus "a wedge," Albanian (Gheg dialect) kân "angle, corner," Albanian (Toks) kënd "angle, corner."

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