An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 442
sâat (#)

Fr.: Horloge   

The Clock. A faint constellation in the southern hemisphere, at about 3h right ascension, 55° south declination. Its brightest star, α Horologii, is of magnitude 3.9. Abbreviation: Hor; Genitive: Horologii.

Horologium "clock," from L., from Gk. horologion, from horolog(os) "timeteller," from horo-, combining form of hora "hour" (→ year) + -log-, stem of legein "to speak, tell" (+ -os adj. suffix) + -ion diminutive suffix.
Originally named Horologium Oscillitorium by Abbé Nicolas Louis de Lacaille (1713-1762) to honour the inventor of the pendulum clock, Christian Huygens (1629-1695).

Sâ'at "clock," from Ar.

zâyecé (#)

Fr.: horoscope   

A schematic drawing showing the positions of the Sun, Moon, and planets at the time of a person's birth for baseless astrological purposes.

From M.Fr. horoscope, from L. horoscopus, from Gk. horoskopos "nativity, horoscope," also "one who casts a horoscope," from hora "hour" + skopos "watching."

Zâyecé "horoscope, thema," from Mid.Pers. zâycag "horoscope," from zâyidan, zâdan, "to give birth, bring forth;" Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" cf. Skt. jan- "to produce, create; to be born," janati "begets, bears;" Gk. gignomai "to happen, become, be born;" L. gignere "to beget;" PIE base *gen- "to give birth, beget."

  ۱) اسب؛ ۲) اسبک   
1) asb (#); 2) asbak (#)

Fr.: cheval   

1) A large, solid-hoofed, herbivorous quadruped, Equus caballus, domesticated since prehistoric times.
2) In a → planispheric astrolabe, the small prominence that, inserted into a slit in the pin, prevents the parts of the instrument from coming loose when in use. The part owes its name to the fact that astrolabe-makers would often shape it into a horse's head (online museo galileo, VirtualMuseum).
See also: → horse latitude, → Horsehead Nebula, → horsepower, → horseshoe mounting, → horseshoe orbit.

Horse, O.E. hors, from P.Gmc. *khursa- (cf. M.Du. ors, Du. ros, O.H.G. hros, Ger. Roß "horse"), of unknown origin; → latitude.

Asb "horse," from Mid.Pers. asp; O.Pers. asa- "horse;" Av. aspa- "horse," aspā- "mare," aspaiia- "pertaining to the horse;" cf. Skt. áśva- "horse, steed;" Gk. hippos; L. equus; O.Ir. ech; Goth. aihwa-; O.E. eoh "horse;" PIE base *ekwo- "horse."

horse latitudes
  وَروناهای ِ اسبی   
varunâhâ-ye asbi

Fr.: calmes tropicaux, latitudes des chevaux   

The belts of latitude over the oceans, located around 30° north and south of the equator, characterized by predominantly calm or light winds and hot and dry weather.

horse; → latitude.
The origin of the term horse latitudes is not clear, despite numerous speculations. A likely explanation appears in Spanish in a natural history text (Historia General y Natural de las Indias by Lopez de Gomara) published in 1535. Therefore, the term derives from El Golfo de las Yeguas, which translates to "The Mares' Sea." The sailors called it this because in the 1500's there was active shipping of horses, particularly brood mares, from Spain to the Canary Islands, and many of the horses died during the transit of this area.

Horsehead Nebula (NGC 2024)
  میغ ِ سر ِ اسب، ~ ِ اسب-سر   
miq-e sar-e asb, ~ asbsar

Fr.: nébuleuse de la Tête de Cheval   

A huge → dark cloud of → interstellar dust that is shaped like a horse's head. It is luminous at its edges because it is in front of the bright → emission nebula IC 434. Its height and width are about 5 and 2.5 → light-years respectively. It is located at a distance of about 1500 light-years in the constellation → Orion. Also known as Barnard 33.

horse; → head; → nebula.

horsepower (hp)
  اسب ِ بخار   
asb-e boxâr (#)

Fr.: cheval-vapeur   

A unit that is used to measure the → power of engines and motors.
1) Metric horsepower is equal to the power required to carry a load of 75 kg over a distance of one meter in one second. It is equivalent to 746 → watts.
2) British (US) horsepower is the rate of work when 33,000 foot-pounds of work are done per minute. The horsepower was defined by James Watt (1736-1819), the inventor of the steam engine, to compare the output of steam engines with the power of draft horses. He determined that a horse is typically capable of a power of 550 foot-pounds per second.

horse; → power.

Asb-e boxâr "vapor horse," translation of Fr. cheval-vapeur, from asb, → horse, + boxâr, → vapor.

horseshoe mounting
  برنشاند ِ نعلی   
barnešând-e na'li

Fr.: monture en fer de cheval   

An equatorial mounting in which the upper end of the polar axis frame is made into a horseshoe shape to accommodate the telescope tube.

Horseshoe, from → horse + shoe, from O.E. scoh "shoe," from P.Gmc. *skokhaz (cf. Dan., Swed. sko, O.S. skoh, Du. schoen, O.H.G. scuoh, Ger. Schuh); → mounting.

Barnešând, → mounting; na'l "horseshoe, shoe," loanword from Ar.

horseshoe orbit
  مدار ِ نعلی   
madâr-e na'li

Fr.: orbite en fer à cheval   

A periodic orbit which passes around the → Lagrangian points L4, L3, and L5, but neither of the two primaries. This orbit is shaped like a horseshoe when viewed in a reference frame rotating with the primaries. Such orbits occur in the solar system, for example in the case of the satellites → Janus and → Epimetheus, which share the same orbit around → Saturn. The smaller Epimetheus encompasses both the L4 and L5 points associated with the larger Janus and performs a horseshoe orbit relative to Saturn and Janus. The satellites experience a close approach every 4 years during which their orbits are exchanged. → tadpole orbit.

horseshoe mounting; → orbit.

šilang (#)

Fr.: tuyau   

A flexible → pipe for conveying a → liquid.

M.E., O.E. akin to Du. hoos, O.N. hosa, Ger. Hose.

Šilang, probably loan from Russ. шлаиг (shlang) "hose."

mizbân (#)

Fr.: hôte   

One that receives or entertains guests especially in his own home. → host galaxy.

M.E. (h)oste, from O.Fr. hoste "guest, host," from L. hospitem (nom. hospes) "guest, host," lit. "lord of strangers," from hostis "stranger."

Mizbân "host," from Mid.Pers. mezdbân "host," from mêzd "offering, meal," Mod.Pers. miz "guest; offering; meal" + -bân a suffix denoting "keeper, guard," sometimes forming agent nouns or indicating relation (e.g. keštibân "sailor;" bâdbân "a sail;" mehrabân "affectionate;" mizbân "host;" âsiyâbân "a miller;" bâqbân "gardener"). This suffix derives from O.Pers. -pāvan- (as in xšaça.pāvan- "satrap"); Av. -pāna- (as in pəšu.pāna- "keeping the passage, bridge guard"), from Proto-Iranian *pa- "to prtotect, keep," → observe, + suffix *-van-; cf. Skt. -pāna- (as in tanū.pāna- "protection of the body").

host galaxy
  کهکشان ِ میزبان   
kahkešân-e mizbân (#)

Fr.: galaxie hôte   

A usually faint galaxy in which a remarkable phenomenon, such as a → supernova event, occurs.

host; → galaxy.

dâq (#)

Fr.: chaud   

Having a relatively high temperature. → hot accretion flow, → hot core, → hot corino, → hot dark matter , → hot dust-obscured galaxy, → hot Jupiter, → hot molecular core, → hot pixel, → hot star.

Hot, O.E. hat, "hot; fervent, fierce," from P.Gmc. *haitoz (cf. Du. heet, Ger. heiß "hot," Goth. heito "heat of a fever").

Dâq "hot; brand, marking," from Mid.Pers. dâq, dâk "hot," dažitan "to burn, scorch," dažišn "burning" (Mod.Pers. dežan (دژن) "acid, pugnent"), from Av. dag-, daž- "to burn;" cf. Skt. dah- "to burn;" L. fovere "to warm, heat; " Arm. dažan "violent, wild;" Lith. degu "to burn;" O.E. fefor; E. fever. PIE base *dhegh- "to burn."

hot accretion flow
  تچان ِ فربال ِ داغ   
tacân-e farbâl-e dâq

Fr.: écoulement d'accrétion chaud   

A type of → accretion flow by a → compact object such as a → black hole which has a high → virial temperature, is → optically thick, and occurs at lower mass → accretion rates compared with → cold accretion flows. In a hot accretion flow with a very low mass accretion rate, the electron mean free path is very large, and so the accreting → plasma is nearly collisionless. In this type of accretion flow, thermal conduction transports the energy from the inner to the outer regions. As the gas temperature in the outer regions can be increased above the → virial temperature , the gas in the outer regions can escape from the gravitational potential of the central black hole and form outflows, significantly decreasing the mass accretion rate.

cold; → accretion; → flow.

hot core
  مغزه‌ی ِ داغ   
maqze-ye dâq

Fr.: cœur chaud   

Same as → hot molecular core.

hot; → core.

hot corino
  مغزک ِ داغ   
maqzak-e dâq

Fr.: petit cœur chaud   

A warm, compact → molecular clump found in the inner envelope of a → Class 0 → protostar. Hot corinos are low-mass analogs of → hot molecular cores (HMCs) occurring in → massive star formation sites. With a typical size of ≤ 150 → astronomical units, hot corinos are two orders of magnitude smaller than HMCs. They have densities ≥ 107 cm-3 and temperatures ≥ 100 K (Ceccarelli, C. 2004, ASP Conf. Ser. 323, 195).

hot; corino, from → core + -ino a diminutive suffix in It.

hot dark matter
  مادّه‌ی ِ تاریک ِ داغ   
mâdde-ye târik-e dâq (#)

Fr.: matière noire chaude   

Any form of → dark matter which had a significant velocity dispersion (comparable to the velocity of light), when the Universe first became → matter-dominated.

hot; → dark; → matter.

hot dust-obscured galaxy (HDOG)
  کهکشان ِ تیره با غبار ِ داغ   
kahkešân-e tiré bâ qobâr-e dâq

Fr.: galaxie obscure à poussière chaude   

A member of the most extreme galaxies in terms of their luminosities and unusual hot → dust temperatures. The → infrared emission from HDOGs is dominated by obscured accretion onto a central → supermassive black hole (SMBH), in most cases without significant contribution from → star formation. The large contrast between the underlying → host galaxy and the hyper-luminous emission from the → active galactic nucleus (AGN) implies that either the SMBH is much more massive than expected for the stellar mass of its host, or is radiating well above its → Eddington limit. The most extreme of these remarkable systems known is → W2246-0526.

hot; → dust; → obscure; → galaxy.

hot electron diode
  دیود ِ الکترون ِ داغ   
diod-e elektron-e dâq

Fr.:diode à électrons chauds   

Same as → Schottky diode

hot; → electron; → diode.

hot Jupiter
  هرمز ِ داغ   
Hormoz-e dâq

Fr.: Jupiter chaud   

A giant, gaseous, Jupiter-like planet lying too close to its parent star and having an orbital period from a few days to a few weeks. The existence of hot Jupiters is usually interpreted in terms of planetary migration. These planets can, in principle, be formed at larger distances from their stars and migrate to the inner regions due to dynamical interaction with the proto-planetary disk.

hot; → Jupiter.

hot molecular core (HMC)
  مغزه‌ی ِ مولکولی ِ داغ   
maqze-ye molekuli-ye dâq

Fr.: cœur moléculaire chaud   

A relatively small, dense, and hot → molecular clump occurring in regions of → massive star formation. HMCs have diameters ≤ 0.1 pc, densities ≥ 107 cm-3, and temperatures ≥ 100 K. The densest hot cores are traced in → ammonia (NH3) and possess densities of 108 cm-3, sizes down to 0.05 pc and temperatures of up to 250 K. Hot molecular cores are generally associated with → compact H II regions and → ultracompact H II regions. High angular resolution observations suggest that HMCs are internally heated by embedded sources, since temperature and density increases toward the center as expected if star formation is occurring close to the core center. Same as → hot core.

hot; → molecular; → core.

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