An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 239 Search : up
25 Orionis group
  گروه ِ ۲۵-شکارگر، ~ ۲۵-اوریون   
goruh-e 25-Šekârgar, ~ 25-Oryon

Fr.: groupe de 25 Orionis   

A group of nearly 200 low-mass → pre-main-sequence stars, concentrated within ~ 1 of the early → B star  → 25 Orionis, in the component a of the → Orion OB1 Association. The group also harbors the → Herbig Ae/Be star V346 Ori and a dozen other early-type stars. The velocity distribution for the low-mass stars shows a narrow peak at 19.7 km s-1, offset ~ 10 km s-1 from the velocity characterizing the younger stars of the Ori OB1b subassociation, and 4 km s-1 from the velocity of widely spread young stars of the Ori OB1a population. This indicates that the 25 Ori group is a distinct kinematic entity. The low-mass members follow a well-defined band in the → color-magnitude diagram, consistent with an age of ~ 7-10 Myr (Briceno et al., 2007, ApJ 661, 1119).

25 Orionis; → group.

Amalthea [Jupiter V]
  آمالتیءا   
Âmâlteâ (#)

Fr.: Amalthée   

The third of Jupiter's known satellites orbiting at about 181,300 km from Jupiter with a period of about 12h. A mean diameter of 189 km makes it the fifth largest satellite of Jupiter. Amalthea was discovered by E. Barnard in 1892.

Amalthea, in Gk. mythology, the goat that suckled Zeus after his mother had him sent to Crete so his father would not eat him.

Ananke [Jupiter XII]
  آننکه   
Ânanké

Fr.: Ananké   

The thirteenth of Jupiter's known satellites discovered by S.B. Nicholson in 1951. It orbits the planet at a mean distance of 21,200,000 km, and has a diameter of about 30 km.

In Gk. mythology, Ananke is the personification of destiny, unalterable necessity and fate; she is also the mother of Adrastea,

backup
  پشتوان   
poštvân (#)

Fr.: sauvegarde   

A copy of computer files that is stored separately from the original in order to protect against loss of data.

Backup "substitute, support," from → back + up.

Poštvân "prop, support, help" from pošt, → back, + -vân suffix denting protection, variant of -bân.

backup program
  برنامه‌ی ِ یدکی   
barnâme-ye yadaki (#)

Fr.: programme de remplacement   

An auxiliary observing program to be carried out at telescope in case the atmospheric conditions make the main program unfeasible.

Backup, from → back + up; → program.

Barnâmé, → program; yadaki "reserve, substitute," from yadak "a led horse."

binary supermassive black hole
  سیه‌چال ِ ابر-پرجرم ِ درین   
siyah-câl-e abar-porjerm-e dorin

Fr.: trou noir supermassif double   

A → dual supermassive black hole whose components are separated by a few parsecs.

binary; → supermassive; → black; → hole.

blue supergiant
  ابرغول ِ آبی   
abarqul-e âbi

Fr.: supergéante bleue   

An evolved star of spectral type O, B, or A; e.g. → Rigel, → Deneb.

blue; → supergiant.

bottom-up structure formation
  دیسش ِ ساختار از پایین به بالا   
diseš-e sâxtâr az pâyin bé bâlâ

Fr.: formation des structures du bas vers le haut   

A → structure formation scenario in which small galaxies form first, and larger structures are then formed in due course. Contrary to → top-down structure formation.

bottom; → up; → structure; → formation; → galaxy.

break-up velocity
  تندای ِ گسست   
tondâ-ye gosast

Fr.: vitesse de rupture   

The velocity of a → rotating star at which the → centrifugal force equals the → gravitational force. Also known as → critical velocity. The simplest expression of the break-up velocity for an OB star, ignoring the → Eddington luminosity, is given by the relation: v = (GM / R)1/2, where M and R are the mass and radius of the star respectively, and G the → gravitational constant. A more realistic expression takes into account not only the → radiation pressure, but also the non-uniformity of the brightness over the stellar surface, as indicated by → von Zeipel theorem. With these conditions, the break-up velocity has a more complicated formula, corresponding to the velocity reached when somewhere on the star the → total gravity becomes zero.

break + up; M.E.; O.E. up, uppe, → hyper-; → velocity.

Callisto (Jupiter IV)
  کالیستو   
Kâlisto (#)

Fr.: Callisto   

The eighth of → Jupiter's known moons and the second brightest and the outermost of the four → Galilean satellites. With a diameter of 4800 km (0.38 Earths), Castillo is roughly the same size as Mercury. It orbits Jupiter in 16.689 days at a distance of 1,883,000 km from the planet, beyond Jupiter's main → radiation belts. It is the third largest moon in the entire solar system. Its mass is 10.76 × 1022 kg (about 1.5 Earth Moons) and its mean → surface temperature is -155 °C. The most prominent feature of Callisto is its craters, as it has the most craters of any object in the solar system. Due to its orbit being further away from Jupiter, it is not under the same → tidal heating influences as → Io, → Europa, or → Ganymede. Callisto's thin → atmosphere is composed of → carbon dioxide and likely some → molecular oxygen. Callisto is thought to have formed as a result of slow → accretion from the → protoplanetary disk of gas and dust that surrounded Jupiter after its formation.

Callisto, an attendant of Artemis in Greek mythology. Because of her love affair with Zeus, she was transformed into a bear by Artemis. According to another legend she was changed into a bear by the jealous Hera. Zeus transferred her to the heavens as the → constellation  → Ursa Major (great bear).

canonical upper limit
  حد ِ زبرین ِ جرم   
hadd-e zabarin-e jerm

Fr.: limite supériure canonique   

A physical upper mass limit near 150 Msun assumed for the stellar → initial mass function (Kroupa et al. 2012, arXiv:1112.3340).

canonical; → upper; → limit.

carbonyl group
  گروه ِ کربونیل   
goruh-e karbonil (#)

Fr.: groupe carbonyl   

The radical -C=O, which occurs in several compounds, such as → aldehydes and ketones.

From → carbon + -yl a suffix used in the names of some radicals; → group.

Carme (Jupiter XI)
  کارمه   
Kârme (#)

Fr.: Carmé   

The fourteenth of Jupiter's known satellites; 40 km in size; → retrograde orbit. It was discovered by Nicholson in 1938.

In Gk mythology, Carme was a wife of Zeus, and the mother of Britomartis, a Cretan goddess.

Centaurus supercluster
  ابرخوشه‌ی ِ کنتاؤروس   
abarxuše-ye Kentawros

Fr.: superamas du Centaur   

The nearest large → supercluster. It is dominated by the → galaxy cluster A3526 (→ Abell catalog). The Centaurus supercluster is a long structure that stretches away from us. The most distant of the clusters, A3581, is about 300 million → light-years away.

Centaurus; → cluster.

central uplift
  بالامد ِ مرکزی   
bâlâmad-e markazi

Fr.: pic central   

Same as → central peak.

central; → up; → lift.

central; → uplift.

charge-coupled device (CCD)
  دستگاه ِ جفسری ِ بار   
dastgâh-e jafsari-ye bâr, sisidi

Fr.: dispositif à transfert de charge   

A solid-state detector that stores the electrons, produced by incident photons, in potential wells at the surface of a semiconductor. The packages of charge are moved about the surface by being transferred to similar adjacent potential wells. The wells are controlled by the manipulation of voltage applied to surface electrodes.

charge; coupled adj. from → couple; → device.

Compton suppression
  نهاوش ِ کامپتون   
nehâveš-e Compton

Fr.: suppression de Compton   

In → gamma ray → spectroscopy, a technique to reduce the contribution of gamma rays generated by → Compton scattering.

Compton; → suppression.

core-collapse supernova
  اَبَر-نو‌اختر ِ رمبش ِ مغزه   
abar-now-axtar-e rombeš-e maqzé

Fr.: supernova à effondrement de coeur   

A supernova arising from the → core collapse of a → massive star. Same as → Type Ib, → Type Ic, or → Type II supernova.

core; → collapse; → supernova.

couple
  ۱) جفت، ۲) جفت‌نیرو؛ ۳) جفتیدن، جفسر کردن   
1) joft (#), 2) joftniru (#); 3) joftidan (#), jafsar kardan

Fr.: 1, 2) couple; 3) coupler   

1) General: Two items of the same kind; a pair; something that joins or connects two things together; a link.
2) A system of two equal and opposite, parallel, but not → collinear forces acting upon a body.
3) To fasten, join together; connect. See also → coupled, → coupled system, → charge-coupled device, → coupling, → decouple, → galvanic couple, → Nasireddin couple, → pair; → parity, → thermocouple.

1) joft "pair, couple," Lori, Laki jeft, Qâyeni jof, Tabari jeft, Mid.Pers. yuxt "pair, couple," Av. yuxta- "a team of horses," from yaog- "to yoke, harness, put to; to join, unite," infinitive yuxta, Mid.Pers. jug, ayoxtan "to join, yoke," Mod.Pers. yuq "yoke," cf. Skt. yugam "yoke," Gk. zygon "yoke," zeugnyanai "to join, unite," L. jugare "to join," from jugum "yoke," P.Gmc. *yukam, E. yoke; PIE *yeug- "to join."
2) joftniru, from joft as above + niru, → force.
3) Joftidan, infinitive from joft, → couple; jafsar kardan infinitive from jafsar, → coupled, + kardan "to do, to make."

coupled
  جفسر، جفتیده   
jafsar, joftidé

Fr.: couplé   

Joined together, connected by a link. → coupled system, → charge-coupled device.

Adj. from → couple.

Jafsar "connected, joined pair," in Tâleši, from jaf, variant of joft, as above + sar "head," literally "joined by head" (Mid.Pers. sar, Av. sarah- "head," Skt. siras- "head," Gk. kara "head," keras "horn," Mod.Pers. sarun "horn," L. cerebrum "brain;" PIE *ker- "head, horn"); joftidé adj./p.p. from joftidan, → couple.

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