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: 7 Search : thick
optical thickness
  ستبرایِ نوری   
setabrâ-ye nuri

Fr.: épaisseur optique   

Same as → optical depth.

optical; → thickness.

optically thick
  نورانه ستبر، نوریکانه ~   
nurâné setabr, nurikâné ~

Fr.: optiquement épais   

The qualifier of a medium in which the → optical depth is large, significantly larger than 1.

optically; → thick.

optically thick wind
  باد ِ نورانه ستبر   
bâd-e nurâné setabr

Fr.: vent optiquement épais   

A wind with the → sonic point located at large optical depth for continuum. In particular, → Wolf-Rayet star winds are → optically thick. However, the outer parts of W-R winds are → optically thin for continuum, and in those regions the matter flow is driven by the same mechanism as in the winds of OB stars.

optically; → thick; → wind.

thick
  ستبر   
setabr (#)

Fr.: épais   

Relatively great in extent from one surface to the opposite; deep or profound. &rarroptically thick

M.E. thikke, O.E. thicce "not thin, dense," from P.Gmc. *theku-, *thekwia- (cf. O.S. thikki, O.H.G. dicchi, Ger. dick), from PIE *tegu- "thick."

Setabr, from Mid.Pers. stabr "strong, big," stambag "pugnacious, opposing;" O.Pers. (mā) stabava [2sg.inj.] "to revolt;" Av. stabra- "strong, firm;" cf. Skt. stabh- "support," stambh- "to support, fix firmly," stabhnāti "supports;" Gk. astemphes "steadfast," stephein "to tie around, encircle," astemphes "firm, rigid;" Lith. stebas "staff, pillar," stembti "to oppose."

thick disk
  گرده‌ی ِ ستبر، دیسک ِ ~   
gerde-ye setabr, disk-e ~

Fr.: disque épais   

A disk component of a → spiral galaxy that lies above the → thin disk and mainly consists of stars. The thick disk of our → Galaxy makes up about 10-50% of the stellar mass of the → Milky Way and has a scale height of ~ 1,000-3,000 → light-years. Thick disk stars are, on average, moving faster in a vertical direction with respect to the → galactic plane than thin disk stars. In contrast to thin disk, the stars within the thick disk are almost all older than 10 billion years and typically have a smaller → metallicity than the average values for the thin disk stars. These facts suggest that the formation scenarios for the thin and thick disks were different. In particular, it is thought that the thick disk is much older than the thin disk.

thick; → disk;

thick lens
  عدسی ِ ستبر   
adasi-ye setabr

Fr.: lentille épaisse   

A lens whose thickness is not small compared with its focal length. The thick lens may include several components, which may or may not be in contact. → thin lens.

thick; → lens.

thickness
  ستبرا   
setabrâ (#)

Fr.: épaisseur   

The state or quality of being thick. → optical thickness.

M.E. thiknesse, O.E. thicnes, from → thick + -nes(s) suffix of action, quality or state, cf. M.Du. -nisse, O.H.G. -nissa, Ger. -nis, Goth. -inassus.

Setabrâ, from setabrthick + a suffix forming nouns from adjectives.