An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 210
-su (#)

Fr.: vers   

A suffix denoting spatial or temporal direction, as specified by the initial element. Also -wards (

M.E., from O.E. -weard "toward," literally "turned toward;" PIE *wert- "to turn, wind," from *wer- "to turn, bend;" cf. Pers. gard-, gardidan "to turn, change," → revolve, → evolve.

-su, → direction.

W 43
W 43

Fr.: W 43   

One of the most massive → star formation regions in the → Galaxy, situated in the constellation → Aquila at the junction point of the → Galactic bar and the → spiral arms. It lies at a distance of about 6 kpc from the Sun and covers a vast area of the → Galactic plane with l = (29° to 32°) and b = (-1° to + 1°). W 43 is a complex of more than 20 → molecular clouds in 13CO emission with systemic velocities ranging from 12 km s-1 to 110 km s-1. The total → virial mass is estimated to be several 106Msun. Close to its center, W 43-Main is undergoing a remarkably efficient episode of → star formation and qualifies as a mini-starburst Among the 15 dense cores of W 43-Main (0.2 pc FWHM size and 5 × 105 cm-3 density), three extremely massive, → dense cores are potentially forming → massive stars: W 43-MM1 (M = 3600 Msun), W 43-MM2 (M = 1600 Msun), and W 43-MM3 (M = 1000 Msun). Adjacent to W 43-Main is a → giant H II region, illuminated by a cluster of → Wolf-Rayet and → OB stars, emitting ~ 1051 → Lyman continuum photons per second and a → far-infrared  → continuum luminosity of ~ 3.5 × 106  Lsun. It is not yet clear what the impact is of this → starburst cluster on the W 43-Main cloud located 2-10 pc away. With its special characteristics, W 43 represents a type of molecular cloud complex which hosts high luminosity embedded clusters. Other well-known examples are W 49 and W 51 (e.g., Nguyen Luong et., 2013, arXiv:1306.0547).

Number 43 in the following catalog: Gart Westerhout, 1958, Bull. Astron. Inst. Netherlands, 14, 215, A survey of the continuous radiation from the galactic system at a frequency of 1390 Mc/s.

W boson
  بوسون ِ W   
boson-e W

Fr.: boson W   

A → boson particle that, along with → Z boson, mediates the → weak force in particle interactions. Two kinds of W bosons exist, the W+ and its antiparticle W-. With a mass of 80.4 GeV/c2, the W boson is almost 100 times as massive as the → proton.

W for → weak; → boson.

W Virginis star
  ستاره‌ی ِ W-دوشیزه   
setâre-ye W dušizé

Fr.: étoile de type W Virginis   

A member of a class of → pulsating stars with a period of 1 to 35 days located in the → instability strip of the → H-R diagram. Also known as type II Cepheid variables, W Virginis stars are typically 1.5 mag fainter than classical Type I Cepheids and have a mass less than that of the Sun. They also exhibit a period-luminosity relation which is distinct, but works in a similar way to the relation for Type I Cepheids. Hence W Virginis stars can also be used to measure Galactic and extragalactic distances.

W, alphabetical letter; → variable star designation; → Virgo; → star.


Fr.: W-R   

Short for → Wolf-Rayet.

Wolf-Rayet star.

W-R star
  ستاره‌ی ِ W-R   
setâre-ye W-R (#)

Fr.: étoile W-R   

Short for → Wolf-Rayet star.

Wolf-Rayet star.


Fr.: W2246-0526   

The most luminous → galaxy known. It has a → redshift of z = 4.601 and a → bolometric luminosity of 3.5 × 1014Lsun. W2246-0526 hosts a deeply buried → active galactic nucleus (AGN)/→ supermassive black hole (SMBH). Discovered using the → Wide-field Infrared Survey Explorer (WISE), W2246-0526 is classified as a → hot dust-obscured galaxy, based on its → luminosity and → dust temperature (T. Diaz-Santos et al. 2015, arXiv:1511.04079).

Object designation from → Wide-field Infrared Survey Explorer (WISE).


Fr.: sillage   

1) The track left by a moving ship.
2) A turbulent region appearing behind an object in a fluid which streams around the object, for example behind an aircraft in flight.

Cognate with M.L.G. wake "wake," Nor. dialect vok, O.N. vok, voka "hole in the ice."

Kel, from Tabari kel, kal "trail, track, footprint."

  ۱) چمیدن، گامیدن؛ ۲) چم، پویش   
1) camidan (#), gâmidan (#); 2) cam; puyeš (#)

Fr.: 1) marcher; 2) marche   

1) To move along on foot at a moderate pace; advance by steps.
2a) An act or instance of walking.
2b) Physics: A moving of a particle among particles. → random walk; → quantum walk.

M.E. walken, from O.E. wealcan "to toss, roll;" cf. O.N. valka "to drag about," Dan. valke "to full," M.Du. walken "to knead, press, full," O.H.G. walchan "to knead," Ger. walken "to full."

Camidan "to walk (proudly)," variant gâmidan "to walk," gâm "step, pace" (related to âmadan "to come," → consequence); Mid.Pers. gâm "step, stride, pace;" O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE stem *gwem- "to go, come."
Puyeš, verbal noun of puyidan "to walk, run, trot; wander," from Mid.Pers. pôy-, pwd- "to run;" cf. Gk. speudein "to hasten;" Lith. spudinti.

Walraven photometry
  شیدسنجی ِ والراون   
šidsanji-ye Walraven

Fr.: photométrie de Walraven   

A photometric system with five wavelength ranges that does not use filters. Instead it uses prisms and lenses (spectroscopy) to select the bands simultaneously. The wavelengths and the bandwidths are: W, 3250 and 140 Å; U, 3630 and 240 Å; L, 3840 and 230 Å; B, 4320 and 450 Å; and V, 5470 and 720 Å. The Walraven photometer was unique in design and remained literally unique as copies were never built. In addition, during its whole life the photometer was mounted permanently on the same telescope that had been built specifically for this instrument, the 91 cm Lightcollector' reflector, which started in 1958 at the Leiden Southern Station in Broederstroom, South-Africa. After 20 years in South-Africa the telescope and photometer were moved to the European Southern Observatory La Silla observatory in Chile. The photometric observations were resumed in March 1979 and continued for another 12 years until the decommissioning of the photometer in 1991.

After the inventors, the Dutch astronomer Theodore Walraven (1916-) and his wife Johanna Helena Walraven, née Terlinden (1920-89); → photometry.

kâhandé (#)

Fr.: descendant   

Decreasing in strength, intensity, power, etc.

Waning, from wane, from M.E. wanen (v.), O.E. wanian "to lessen;" cf. O.S. wanon, O.N. vana, O.Fris. wania, M.Du. waenen, O.H.G. wanon "to wane, to grow less."

Kâhandé "waning, decreasing;" from kâstan, kâhidan "to decrease;" Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little" (Mod.Pers. keh); Proto-Iranian *kas- "to be small, diminish, lessen."

waning crescent
  هلال ِ کاهنده، برن ِ ~   
helâl-e kâhandé, barn-e ~

Fr.: croissant descendant   

The crescent phase of the moon following the → last quarter.

waning; → crescent.

waning gibbous
  کوژماه ِ کاهنده   
kužmâh-e kâhandé

Fr.: lune gibbeuse descendante   

The oval shape of the moon a few days after the → full moon and before the → last quarter.

waning; → gibbous.

waning moon
  ماه ِ کاهنده   
mâh-e kâhandé (#)

Fr.: lune descendante   

The circumstance when the phase of the Moon is decreasing from → full moon to → new moon.

waning; → moon.

garm (#)

Fr.: tiède   

Moderately hot.

M.E.; O.E. wearm (cf. O.S., O.Fris., M.Du., O.H.G., Ger. warm, O.N. varmr, Goth. warmjan "to warm"); cognate with Pers. garm, as below.

Garm "warm;" Mid.Pers. garm "warm;" O.Pers. garma-pada "name of the fourth month" (June-July); Av. garəma- "warm; heat;" cf. Skt. gharmá "heat;" Gk. therme, thermos; L. formus "warm;" E. warm, as above; PIE base *ghworm-/*ghwerm- "warm."

warm absorber
  درشمگر ِ گرم   
daršamgar-e garm

Fr.: absorbeur chaud   

A cloud of ionized gas within → active galactic nuclei (AGN) that causes absorption at → soft X-ray wavelengths. Warm absorbers were first suggested by Halpern (1984) to explain Einstein data of the quasar MR 2251-178. They are dubbed "warm" absorbers as they imply gas at temperatures of 104-105 K; the gas is → photoionized, not collisionally ionized. High resolution observations of warm absorbers have shown that they are outfowing. See also → cold absorber (Ceri Ellen Ashton, 2005, A Study of Warm Absorbers in Active Galactic Nuclei, Thesis, Mullard Space Science Laboratory Department of Space and Climate Physics University College London ).

warm; → absorber.

warm front
  پیشان ِ گرم   
pišân-e garm

Fr.: front chaud   

Meteo.: A leading edge that advances in a mass of air and replaces cooler air by warm air.

warm; → front.

warm intercloud medium
  مدیم ِ اندر-ابری ِ گرم   
madim-e andarabri-ye garm

Fr.: milieu internuage chaud   

A component of the → interstellar medium consisting of an extremely tenuous (density 0.1 to 10 cm-3) and relatively warm gas (temperature about 8,000 K) filling the space between denser neutral and ionized gas. Hydrogen is partly ionized, partly atomic and observed by the → 21-centimeter line in emission.

warm; → intercloud medium.

warm-hot intergalactic medium
  مدیم ِ اندر-کهکشانی ِ گرم-داغ   
madim-e andar-kahkašâni garm-dâq

Fr.: milieu intergalactique chaud   

The space containing a cluster of galaxies filled with a tenuous gas of temperature 105 to 107 K and density 10-6 to 10-4 cm-3. WHIM has been continuously shock-heated during the process of structure formation. It is so highly ionized that it can only absorb or emit far-ultraviolet and soft X-ray photons, primarily at spectral lines of highly ionized C, O, Ne, and Fe. WHIM is thought to be the main reservoir of missing baryons.

warm; → hot; → intergalactic medium.

garmâyeš (#)

Fr.: réchauffement   

The process of becoming warmer; a rising temperature. → backwarming, → heating.

warm; → -ing.

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