An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < A s bim col ext gui lat OBN Pop red spi Sta ult wea ZZ > >>

Number of Results: 261 Search : star
ultraviolet star
  ستاره‌ی ِ فرابنفش، ~ ِ اولتر-بنفش   
setâre-ye farâbanafš, ~ ultar-banafš

Fr.: étoile ultraviolette   

A star, such as O types or hot central stars of planetary nebulae, which radiates essentially in the ultraviolet part of the electromagnetic spectrum.

ultraviolet; → star.

unclassified B[e] star (unclB[e])
  ستاره‌یِ B[e]ی ِ بی‌رده   
setâre-ye B[e]-ye bi radé

Fr.: étoile B[e] non-classée   

A temporary designation for a → B[e] star that cannot be placed in any of the four known classes.

classification; → B[e] star.

unreddened star
  ستاره‌ی ِ ناسرخیده   
setâre-ye nâsorxidé

Fr.: étoile non rougie   

A star whose light is not affected by→ interstellar absorption. → reddening

un-; → reddened star.

Ursa Major star cluster
  خوشه‌ی ِ خرس ِ بزرگ   
xuše-ye Xers-e Bozorg (#)

Fr.: amas de la Grande Ourse   

A moving star cluster containing over 100 stars that are scattered over an area of sky more than 1,000 minutes of arc in diameter. The five brightest stars of the → Big Dipper as well as → Sirius belong to this → dynamical stream.

Ursa Major; → star; → cluster.

UX Ori star
  ستاره‌ی ِUX شکارگر   
setâre-ye UX Šekârgar

Fr.: étoile UX Ori   

A star that shows large irregular brightness variations and belongs to the Herbig Ae/Be family, i.e. pre-main sequence stars of intermediate mass. Typically a decrease of 2-3 magnitudes in the visible occurs for a few days to a couple of weeks. Current theories explain this behavior as being an obscuration of the central star by orbiting dust clouds, as well as contribution to the total luminosity by unsteady accretion onto the central star. Also called UXOr.

U and X letters of alphabet, Ori, → Orion; → star.

variable star
  ستاره‌ی ِ ورتنده   
setâre-ye vartandé

Fr.: étoile variable   

A star whose luminosity changes over periods of time; there are many reasons and many types. → cataclysmic variable; → Cepheid; → pulsating star; → nova; → long-period variable; → short-period variable; → Luminous Blue Variable (LBV); etc.

variable; → star.

variable star designation
  نامگزینی ِ ستاره‌ی ِ ورتنده   
nâmgozini-ye setâre-ye vartandé

Fr.: designation des étoiles variables   

A set of conventions used for naming → variable stars. Stars with existing → Bayer designations are not given new designations. Alternatively, the letters R through Z are used followed by the Latin genitive of the name of the hosting constellation. Otherwise, two letters of alphabet are used (334 combinations) with the Latin genitive of the name of the constellation. Finally, the letter V (variable) is used followed by numbers 335, 336, and so on. Some examples are: → P Cygni, → T Tauri, → FU Orionis, → EX Lupi, and → V2052 Oph.

variable; → star; → designation.

very low-mass star
  ستاره‌ی ِ بسیار کم‌جرم   
setâre-ye besyâr kamjerm

Fr.: étoile de très faible masse   

A star with a typical mass of one-hundredth of the mass of the Sun (→ solar mass) and a luminosity of about one-millionth that of the Sun (→ solar luminosity). Same as → brown dwarf.

very; → low; → mass; → star.

very massive star
  ستاره‌ی ِ بسیار پرجرم   
setâre-ye besyâr porjerm

Fr.: étoile très massive   

A star of mass around 100 → solar masses. See also: → supermassive star, → massive star, → canonical upper limit.

very; → massive; → star.

violent star formation
  دیسش ِ سورای ِ ستارگان   
diseše surâ-ye setâregân

Fr.: formation violente d'étoiles   

The concept of star formation pertaining to a variety of systems (OB associations, giant H II regions, H II galaxies, massive star clusters, etc.) that are believed to have formed large numbers of stars in a very short time.

violent; → star formation.

Vz star
  ستاره‌ی ِ Vz   
setâre-ye Vz

Fr.: étoile de type Vz   

A class of → O-type stars whose spectra show He II 4686 absorption line much stronger than any other He line especially He II 4541 or He I 4471. Vz stars are thought to be young stars lying close to the → ZAMS (Walborn & Parker 1992, ApJ 399, L87). Alternatively, the Vz characteristics may be related to the wind properties rather than to the youth of the star (Martins et al., 2005, A&A 441, 735).

V indicating → main sequence, z for "zero age;" → star.

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.

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

Fr.: étoile W-R   

Short for → Wolf-Rayet star.

Wolf-Rayet star.

Washington Double Star Catalog
  کاتالوگ ِ ستارگان ِ دوتایی ِ واشینگتن   
kâtâlog-e setâregân-e dotâyi-ye Washington

Fr.: Washington Double Star Catalogue   

A stellar catalog which is the world's principal database of astrometric → double star information. It is maintained by the United States Naval Observatory. The WDS Catalog contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 142552 systems (as of Feb 27 2018).

Washington, referring to the location of the United States Naval Observatory in Northwest Washington, D.C; → double; → star; → catalog.

WC4 star
  ستاره‌ی WC4   
setâre-ye WC4

Fr.: étoile WC4   

A → WC Wolf-Rayet that its spectrum shows the following emission line characteristics: strong C IV 5801-12 Å, weak or absent C II 4267 Å, and moderate O V 5572-98 Å.

W, from → Wolf-Rayet; C, from → carbon; → star.

WC5 star
  ستاره‌ی WC5   
setâre-ye WC5

Fr.: étoile WC5   

A → WC Wolf-Rayet whose spectrum shows the following emission line characteristics: C III 5696 Å very weaker than C IV 5801-12 Å and C III weaker than O V 5572-98 Å.

W, from → Wolf-Rayet; C, from → carbon; → star.

WC6 star
  ستاره‌ی WC6   
setâre-ye WC6

Fr.: étoile WC6   

A → WC Wolf-Rayet whose spectrum shows the following emission line characteristics: C III 5696 Å very weaker than C IV 5801-12 Å and C III stronger than O V 5572-98 Å.

W, from → Wolf-Rayet; C, from → carbon; → star.

WC7 star
  ستاره‌ی WC7   
setâre-ye WC7

Fr.: étoile WC7   

A → WC Wolf-Rayet with a spectrum shows the following emission line characteristics: C III 5696 Å weaker than C IV 5801-12 Å and C III very stronger than O V 5572-98 Å.

W, from → Wolf-Rayet; C, from → carbon; → star.

WC8 star
  ستاره‌ی WC8   
setâre-ye WC8

Fr.: étoile WC8   

A → WC Wolf-Rayet with a spectrum shows the following emission line characteristics: C III 5696 Å stronger than C IV 5801-12 Å, C II 4267 Å absent, and O V 5572-98 Å weak or absent.

W, from → Wolf-Rayet; C, from → carbon; → star.

WC9 star
  ستاره‌ی WC9   
setâre-ye WC9

Fr.: étoile WC9   

A → WC Wolf-Rayet whose spectrum shows the following emission line characteristics: C III 569 Å stronger than C IV 5801-12 Å, C II 4267 Å present, and O V 5572-98 Å weak or absent.

W, from → Wolf-Rayet; C, from → carbon; → star.

<< < A s bim col ext gui lat OBN Pop red spi Sta ult wea ZZ > >>