An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 247 Search : star
comparison star
  ستاره‌ی ِ هم‌سنجش   
setâre-ye hamsanješ

Fr.: étoile de comparaison   

A non-variable star used to monitor the variations of another nearby star.

comparison; → star.

cosmic star formation peak
  چکاد ِ کیهانی ِ دیسش ِ ستارگان   
cakâd-e keyhâni-ye diseš-e setâregân

Fr.: pic de formation stellaire cosmique   

A crucial period in the history of the → Universe, when the bulk of stars in massive galaxies were likely formed. Observations of young stars in distant galaxies at different times in the past have indicated that the → star formation rate peaked at the → redshift of z ~ 2, some 10 billion years ago, before declining by a factor of around ten to its present value (P. Madau & Dickinson, 2014, arXiv:1403.0007).

cosmic; → star; → formation; → peak.

dark star
  ستاره‌ی ِ تاریک   
setâre-ye târik

Fr.: étoile noire, ~ sombre   

A hypothetical stellar object whose structure or evolution has been affected by → dark matter. Dark matter models predict that in the → early Universe dark matter (in the form of → WIMPs) should congregate and annihilate in the cores of → Population III stars. The result would be dark stars with properties very different from ordinary stars. The reason is that the presence of large amounts of dark matter during the formation of a star inhibits the collapse and can partially prevent further cooling of the gas beyond a certain critical point, well before a → main sequence object has formed. As a consequence, dark matter stars should be more massive, more luminous, and live longer than Pop. III stars, but would be cooler. The formation of dark stars could have had an impact on the → reionization history of the Universe (see, e.g., P. Scott, 2011, astro-ph/1101.1029, and references therein).

dark; → star.

disk star
  ستاره‌ی ِ گرده، ~ دیسک   
setâre-ye gerdé, ~ disk

Fr.: étoile de disque   

A star that lies within the → galactic disk of a → spiral galaxy. Stars belonging to the → thin disk, such as the Sun or Alpha Centauri, lie at a typical distance of about 1,000 → light-years from the galactic midplane. There are also → thick disk stars, such as Lalande 21185, that lie at an average distance of about 3,500 light-years from the midplane.

disk; → star.

donor star
  ستاره‌ی ِ دهنده   
setâre-ye dahandé

Fr.: étoile donneuse   

In a → binary system, a star whose gas is → accreted by a compact companion. The donor may be a → giant or a → supergiant with an enormously distended atmosphere and a significant → stellar wind, or a star filling its → Roche lobe in a → close binary.

donor; → star.

double star
  ستاره‌ی ِ دوتایی   
setâre-ye dotâyi (#)

Fr.: étoile double   

An apparently single star which better observational resolution shows it to be a pair of closely lying stars. They may or may not be physically related.

double; → star.

dwarf star
  ستاره‌ی ِ کوتوله   
setâre-ye kutulé (#)

Fr.: étoile naine   

A star that burns its hydrogen content to produce its energy and therefore belongs to the main-sequence luminosity class.

dwarf; → star.

early spectral class star
  ستاره با رده‌ی ِ بینابی ِ آغازین   
setâré bâ rade-ye binâbi-ye âqâzin

Fr.: étoile de type spectral précoce   

A star near the beginning of the → spectral classification sequence. A star of → spectral type O, B, A, or F0 to F5. Same as → early-type star.

early; → spectral; → class; → star.

early-type star
  ستاره‌ی ِ گونه‌ی ِ آغازین   
setâre-ye gun-ye âqâzin (#)

Fr.: étoile de type précoce   

Hot, luminous stars of → spectral type O, B, A, and F0 to F5. They were originally thought, wrongly, to be at an earlier stage of evolution than → late-type stars. See also → spectral classification.

early; → type; → star.

EHB star
  ستاره‌ی ِ EHB   
setâre-ye EHB

Fr.: étoile EBH   

Same as → extreme horizontal branch star.

extreme horizontal branch star.

electroweak star
  ستاره‌ی ِ برقانزار   
setâre-ye barqânezâr

Fr.: étoile électrofaible   

A postulated type of star that could form toward the end of a → massive star's life, after → nuclear fusion has stopped in its → core, and before the star → collapses into a → black hole. In those → extreme conditions, when → temperature and → density inside the star are very high, → quarks could convert into → leptons. Hence huge amounts of energy can be released, much of which would be in the form of → neutrinos.

electroweak; → star.

embedded star
  ستاره‌ی ِ فروپوشیده   
setâre-ye forupušidé

Fr.: étoile enfouie   

A newborn star which is tightly enveloped by a surrounding cloud of gas and dust.

Ebedded p.p. of embed, from en- + bed from O.E. bed "bed," from P.Gmc. *badjam "sleeping place dug in the ground" (O.H.G. betti; Ger. bett); PIE base *bhedh- "to dig, pierce;" cf. Gk. bothyros "pit;" L. fodere "to dig," fossa "ditch;" → star.

Setâré, → star; forupušidé, p.p. of forupušidan, from foru- "below; beneath; down, downwards;" Mid.Pers. frôt "down, downwards;" O.Pers. fravata "forward, downward;" Skt. pravát- "a sloping path, the slope of a mountain" + pušidan "to cover, conceal, clothe; to wear clothes;" Mid.Pers. pôšidan, pôš- "to cover, put on, wear;" cf. Mid.Pers. pôst; Mod.Pers. pust "skin, hide;" O.Pers. pavastā- "thin clay envelope used to protect unbaked clay tablets;" Skt. pavásta- "cover;" Proto-Indo-Iranian *pauastā- "cloth."

evening star
  ستاره‌ی ِ شامگاه   
setâre-ye šâmgâh (#)

Fr.: étoile du soir   

Any bright → planet, often → Venus, seen low in the western sky after → sunset. → Hesperus.

evening; → star.

evolved star
  ستاره‌ی ِ فرگشته   
setâreye fargašté

Fr.: étoile évoluée   

A star that has left the → main sequence.

evolve; → star.

exciting star
  ستاره‌ی ِ بر انگیزنده   
setâre-ye barangizandé

Fr.: étoile excitatrice   

A star associated with an interstellar ionized nebula (→ H II region or → planetary nebula) whose energetic → ultraviolet, → photons → ionize the nebula.

Exciting, verbal adj. of → excite; → star.

exotic star
  ستاره‌ی ِ اسگانیک   
setâre-ye osgânik

Fr.: étoile exotique   

A hypothetical → compact object composed of particles other than electrons, protons, and neutrons balanced against → gravitational collapse by → degeneracy pressure of corresponding quantum properties.

exotic; → star.

extinction stars
  ستارگان ِ خاموشی   
setâregân-e xâmuši

Fr.: étoiles d'extinction   

Stars specifically observed at selected air masses in view of determining the atmospheric extinction coefficients.

extinction; → star.

extreme HB star
  ستاره‌ی ِ EHB   
setâre-ye EHB

Fr.: étoile EBH   

Same as → extreme horizontal branch star.

extreme horizontal branch star.

extreme horizontal branch star (EHB)
  ستاره‌ی ِ شاخه‌ی ِ افقی ِ استوم   
setâre-ye šâxe-ye ofoqi-ye ostom

Fr.: étoile de la branche horizontale extrême   

The hottest variety of stars on the → horizontal branch with temperatures ranging from 20,000 to 40,000 K. EHB stars are distinguished from normal horizontal branch stars by having extremely thin, inert hydrogen envelopes surrounding the helium-burning core. They are hot, dense stars with masses in a narrow range near 0.5 Msun. These stars have undergone such extreme mass loss during their first ascent up the giant branch that only a very thin hydrogen envelope survives. Stars identified as EHB stars are found in low metallicity globular clusters as an extension of the normal HB.

extreme; → horizontal; → branch; → star.

extremely metal-poor star (EMPS)
  ستاره‌ی ِ اُستومانه کم‌فلز   
stâre-ye ostomâné kamfelez

Fr.: étoile extrêmement faible en métaux   

A star with an iron abundance [Fe/H] < -3 found in a → galactic halo. These stars, whose → metallicity is typically less than one thousandth of the solar value, are believed to have formed shortly after the → Big Bang, 13.7 billion years ago. The number of such stars depends on the primordial → initial mass function. If the IMF were steep, there could, in principle, be a lot of EMPSs formed at high → redshifts. Thus many of them could have ended up in the halos of galaxies. See also → Population III star.

extreme; → metal; → poor; → star.

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