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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 554
Type I supernova
  ابر-نو-اختر ِ گونه‌ی ِ I   
abar-now-axtar-e gune-ye I

Fr.: supernova de type I   

A type of supernova whose spectra lacks hydrogen lines. Its → light curve exhibits a sharp maximum with a gradual decrease. Typical magnitudes MV = -14 to -17. Ejecta velocities about 10,000 km/sec. Type I supernovae have several subtypes: → Type Ia, → Type Ib, and → Type Ic.

Type I initially introduced by R. Minkowski (1941, PASP 53, 224); → type; → supernova.

Type I tail
  دم ِ گونه‌ی ِ I   
dom-e gune-ye I

Fr.: queue de type I   

The → gas tail of of a comet.

type; → tail.

Type Ia supernova
  ابر-نو-اختر ِ گونه‌ی ِ Ia   
abar-now-axtar-e gune-ye Ia

Fr.: supernova de type Ia   

A → Type I supernova that presents a singly-ionized silicon (Si II) absorption feature at 6150 Å near peak brightness. Type Ia SNe are believed to result from mass → accretion to a carbon-oxygen → white dwarf in a → close binary system. When the white dwarf mass exceeds the → Chandrasekhar limit, the → degenerate electron pressure can no longer support the accumulated mass and the star collapses in a thermonuclear explosion producing a supernova. The → peak luminosity of SNe Ia is set by the radioactive decay chain 56Ni → 56Co → 56Fe, and the observed photometric correlation between the peak luminosity and the time-scale over which the → light curve decays from its maximum is understood physically as having both the luminosity and → opacity being set by the mass of 56Ni synthesized in the explosion. Type Ia supernovae occur in all types of galaxies. Type Ia SNe are used as → standard candles in determining cosmological distances, after normalizing their light curves with the → Phillips relation.

type; → supernova.

Type Ib supernova
  ابر-نو-اختر ِ گونه‌ی ِ Ib   
abar-now-axtar-e gune-ye Ib

Fr.: supernova de type Ia   

A → Type I supernova that has neutral helium line (He I) at 5876 Å, and no strong silicon (Si II) absorption feature at 6150 Å. Type Ib supernovae are believed to result from the evolution of → massive stars.

type; → supernova.

Type Ic supernova
  ابر-نو-اختر ِ گونه‌ی ِ Ic   
abar-now-axtar-e gune-ye Ic

Fr.: supernova de type Ia   

A → Type I supernova that shows weak or no helium lines and no strong silicon (Si II) absorption feature near 6150 Å. Type Ic supernovae are believed to result from the evolution of → massive stars.

type; → supernova.

Type II burst
  بلک ِ گونه‌ی ِ II   
belk-e gune-ye II

Fr.: sursaut de type II   

A burst of → X-rays observed toward → low-mass X-ray binary (LMXB)s and characterized by quick succession of bursts with recurrence intervals as short as ~ 7 s. Type II X-ray bursts look similar to → Type I bursts, but they are thought to be related with spasmodic episodes of → accretion.

type; → burst.

Type II error
  ایرنگ ِ گونه‌ی ِ II   
irang-e gune-ye II

Fr.: erreur de type II   

Statistics: An error made if a → hypothesis is accepted when it should be rejected. → Type I error.

type; → error.

Type II migration
  کوچ ِ گونه‌ی ِ II   
kuc-e gune-ye II

Fr.: migration de type II   

The → orbital migration of forming → planets that → accrete enough disk material to exceed the critical mass. This type migrates in a gap created in the → protoplanetary disk. Compare with → Type I migration.

type; → migration.

Type II supernova
  ابر-نو-اختر ِ گونه‌ی ِ II   
abar-now-axtar-e gune-ye II

Fr.: supernova de type II   

A supernova type whose spectrum contains hydrogen lines. Compared with → Type I supernovae, its → light curve has a broader peak at maximum and dies away more rapidly. The magnitudes are smaller, ranging from MV = -12 to -13.5, and the ejecta have lower velocities (about 5,000 km/sec). These supernovae, which result from the final evolution of → massive stars, have three main divisions: → Type II-P, → Type II-L, and → Type II-n.

Type II initially introduced by R. Minkowski (1941, PASP 53, 224); → type; → supernova.

Type II tail
  دم ِ گونه‌ی ِ II   
dom-e gune-ye II

Fr.: queue de type II   

The → dust tail of a → comet.

type; → tail.

Type II-L supernova (SN II-L)
  ابر-نو-اختر ِ گونه‌ی ِ II-L   
abar-now-axtar-e gune-ye II-L

Fr.: supernova de type II-L   

A → Type II supernova which displays a linear decrease in its → light curve.

Type II supernova; L short for → linear.

Type II-n supernova (SN II-n)
  ابر-نو-اختر ِ گونه‌ی ِ II-n   
abar-now-axtar-e gune-ye II-n

Fr.: supernova de type II-n   

A → Type II supernova which shows intermediate or very narrow width hydrogen → emission lines in the spectra.

Type II supernova; n short for → narrow.

Type II-P supernova (SN II-P)
  ابر-نو-اختر ِ گونه‌ی ِ II-P   
abar-now-axtar-e gune-ye II-P

Fr.: supernova de type II-P   

A → Type II supernova which reaches a plateau in its → light curve. The vast majority of Type II SNe are characterized by a fast (few days) rise to a flat light curve, most pronounced in the reddest optical bands, with a duration of 80-100 days. This plateau phase is interpreted as the recession of the photosphere as the ejecta expand and cool. The spectra of SNe II-P are typically dominated by strong → P Cygni profiles of hydrogen lines, as well as iron absorption features (for a review, e.g., see Filippenko 1997, ARA&A 35, 309).

Type II supernova; P short for → plateau.

typical
  گونه‌وار   
gune-vâr

Fr.: typique   

Having all or most of the characteristics shared by others of the same kind and therefore suitable as an example of it.

From M.L. typicalis "symbolic," from L.L. typicus "of or pertaining to a type," from Gk. typikos, from typos "impression," from typ(os) + -ikos, → -ic.

Gune-vâr, from guné, → type, + -vâr a suffix meaning "resembling, like" (Mid.Pers. -wâr, Av. -vara, -var, cf. Skt. -vara).

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