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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<< < A s Bla com ext hor mul pec pro sca sta sym WC4 WN7 > >>

Number of Results: 247 Search : star
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.

weak emission-line central star (wel)
  ستاره‌ی ِ مرکزی با خط ِ گسیلی ِ نزار   
setâre-ye markazi bâ xatt-e gosili-ye nezâr

Fr.: étoile centrale à faibles raies d'émission   

A member of a class of cntral stars of planetary nebula, → CSPN, which have weaker and narrower emission lines than → Wolf-Rayet-like CSPNe (Tylenda et al. 1993, A&AS 102, 595).

weak; → emission; → line.

weak-line T Tauri star
  ستاره‌ی ِ T-گاو با خط‌های ِ نزار   
setâre-ye T-Gâv bâ xatthâ-ye nezâr

Fr.: étoile T Tauri à raies faibles   

A T Tauri star that lacks strong emission lines in its optical spectrum, and lacks both strong → stellar wind and → infrared excess. These objects are believed to be → pre-main sequence stars without obvious signs for disk → accretion. Weak-line T Tauri stars result from the evolution of → classical T Tauri stars.

weak; → line; → T Tauri star.

weak-wind O-type star
  ستاره‌ی ِ O با باد ِ نزار، ~ ~ ~ ~ کمزور   
setâre-ye O bâ bâd-e nezâr, ~ ~ ~ ~ kamzur

Fr.: étoile O de faible vent   

A → main sequence → O star with low luminosity and surprisingly weak → stellar wind compared to "classical" dwarfs. The → mass loss rates are lower than 10-8 solar masses per year and the → modified wind momenta nearly 2 orders of magnitude smaller than that expected from wind models for typical O stars. Weak-wind O-type stars occur in both → metal-rich and → metal-poor environments. Their nature is not yet fully understood. same as → weak wind problem.

weak; → wind; → O-type star.

WN/WC star
  ستاره‌ی ِ WN/WC   
setâre-ye WN/WC

Fr.: étoile WN/WC   

An object showing signatures of both → WN Wolf-Rayet stars and → WC Wolf-Rayet stars in the same spectrum, originating from individual stars rather than from WN + WC → binary systems. Such a WN/WC signature implies that the surface composition of the star is → nitrogen and → carbon enriched. This hybrid state results from a mixing process between He-burning → convective core and the overlying nitrogen enriched layers. According to model predictions, this situation corresponds to a short transition phase, lasting 103 to 104 years, during which a WN star evolves into a WC star. The WN/WC stars so far detected are all of early types.

WN Wolf-Rayet; → WC Wolf-Rayet.

WN10 star
  ستاره‌ی ِ WN10   
setâre-ye WN10

Fr.: étoile WN10   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å as strong as N II 3995 Å, Balmer lines, He I with → P Cygni profile.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN11 star
  ستاره‌ی ِ WN11   
setâre-ye WN11

Fr.: étoile WN11   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N II 3995 Å as strong as He II 4686 Å, N III 4634-4641, 5314 Å weak or absent, Balmer lines, He I with → P Cygni profile.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN2 star
  ستاره‌ی ِ WN2   
setâre-ye WN2

Fr.: étoile WN2   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N V 4603, 4619 Å weak or absent,He II 4686 Å strong.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN2.5 star
  ستاره‌ی ِ WN2.5   
setâre-ye WN2.5

Fr.: étoile WN2.5   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N V 4603, 4619 Å present, N IV 3479-3484, 4058 Å absent.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN3 star
  ستاره‌ی ِ WN3   
setâre-ye WN3

Fr.: étoile WN3   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N IV 3479-3484, 4058 Å very weaker than N V 3479-3484, 4058 Å and N III 4634-4641, 5314 Å weak or absent.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN3/O3 star
  ستاره‌ی ِ WN3/O3   
setâre-ye WN/O3

Fr.: étoile WN3/O3   

A new type of → Wolf-Rayet stars found in the → Large Magellanic Cloud (LMC). These stars have both strong → emission lines, as well as → He II lines and → Balmer lines in absorption and spectroscopically resemble a → WN3 and → O3V binary pair. However, they are visually too faint to be WN3+O3 V → binary systems. So far nine WN3/O3 types have been detected, making up ~ 6% of the population of LMC WRs. Their temperatures are estimated to be around 100,000 K, a bit hotter than the majority of → WN Wolf-Rayet stars (by around 10,000 K) although a few hotter WNs are known. The abundances are what you would expect for → CNO equilibrium. However, most anomalous are their → mass-loss rates which are more like that of an → O star than a WN star. While their evolutionary status is uncertain, their low mass-loss rates and → wind velocities suggest that they are not products of homogeneous evolution. It is possible instead that these stars represent an intermediate stage between O stars and WNs. Since WN3/O3 stars are unknown in the Milky Way, their formation would depend upon → metallicity (Neugent et al., 2017, arxiv:1704.05497).

WN3; → O3; → star.

WN4 star
  ستاره‌ی ِ WN4   
setâre-ye WN4

Fr.: étoile WN4   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N IV 3479-3484, 4058 Å about N V 3479-3484, 4058 Å and N III 4634-4641, 5314 Å weak or absent.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN4.5 star
  ستاره‌ی ِ WN4.5   
setâre-ye WN4.5

Fr.: étoile WN4.5   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N IV 3479-3484, 4058 Å stronger than N V 3479-3484, 4058 Å and N III 4634-4641, 5314 Å weak or absent.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN5 star
  ستاره‌ی ِ WN5   
setâre-ye WN5

Fr.: étoile WN5   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å as strong as N IV 3479-3484, 4058 Å as strong as N V 3479-3484, 4058 Å.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

WN6 star
  ستاره‌ی ِ WN6   
setâre-ye WN6

Fr.: étoile WN6   

A → WN Wolf-Rayet star whose spectrum shows the following emission line characteristics: N III 4634-4641, 5314 Å about N IV 3479-3484, 4058 Å and N V 3479-3484, 4058 Å present, but weak.

W, from → Wolf-Rayet; N, from → nitrogen; → star.

<< < A s Bla com ext hor mul pec pro sca sta sym WC4 WN7 > >>