An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1353
sodium tail
  دم ِ سودیومی   
dom-e sodiomi

Fr.: queue de sodium   

1) A kind of → cometary tail appearing in some → comets, such as → Hale-Bopp. Sodium tails arise from the very strong → fluorescence of their sodium atom → D lines in the visible. They are rapidly accelerated to high velocities by the Sun, forming a very straight tail distinct from the → ion tail. The release mechanism of sodium from comets is still a matter of debate. Also called → neutral tail.
2) An enormous, comet-like tail of sodium gas stretching out behind the Moon, at least 800,000 km (many hundreds, and perhaps thousands, of lunar radii). The tail is due to the strong influence of the Sun's → radiation pressure on sodium atoms (→ D line) present in the → lunar exosphere. Near → new Moon phase, the extended lunar sodium tail can be observed as it sweeps over the Earth and is gravitationally focused into a visible sodium "spot" in the → anti-solar direction. It is too faint to be detected by the human eye.

sodium; → tail.

narm (#)

Fr.: mou   

General: Delicate in texture, grain, or fiber.
Not bright or glaring.
Physics: Of a beam of particles or electromagnetic radiation, having relatively low energy, as opposed to → hard. → soft X-rays

M.E. softe "yielding, gentle, mild;" O.E. softe "gentle, easy;" cf. O.S. safti, O.H.G. semfti, Ger. sanft, M.Du. sachte, Du. zacht.

Narm "soft; smooth; mild," from Mid.Pers. narm "soft; humble."

soft binary
  درین ِ نرم   
dorin-e narm

Fr.: binaire mou   

In → stellar dynamics studies of → three-body encounters, a → binary system whose → binding energy is smaller than the typical → kinetic energy of the relative motion of an incoming third body. See also → hard binary.

soft; → binary.

soft gamma repeater (SGR)
  بازگرشگر ِ گامای ِ نرم   
bâzgaršgar-e gâmmâ-ye narm

Fr.: répéteur gamma mou   

A member of a small class of objects which emit intense bursts of → gamma rays and → X-rays (> 100 keV) at irregular intervals. The bursts last for some 100 milli-seconds. It is conjectured that they are → magnetars. See also → starquake.

soft; → gamma rays; → repeater.

soft gamma-ray repeater (SGR)
  بازگرشگر ِ پرتوهای ِ گامای ِ نرم   
bâzgaršgar-e partowhâ-ye gâmmâ-ye narm

Fr.: répéteur des rayons gamma mous   

Same as → soft gamma repeater (SGR).

soft; → gamma ray; → repeater.

soft iron
  آهن ِ نرم   
âhan-e narm

Fr.: fer doux   

Iron that has a low carbon content, in contrast to → steel. Because it is easily magnetized and demagnetized, it is used to make the cores of → solenoids and other electrical equipment.

soft; → iron.

soft palate
narmkâm (#)

Fr.: voile du palais, palais mou, velum   

The back, muscular (not bony) part of the roof of the → mouth in front of the → pharynx.

soft; → palate.

Soft X-ray Transient (SXT)
  گذرای ِ پرتو ِ ایکس ِ نرم   
gozarâ-ye partow-e X-e narm


An → X-ray binary system that has a long period of → quiescence interrupted by → outbursts of low-energy → soft X-rays. Alternatively known as X-ray novae, the majority (~ 75%) of SXTs contain a → black hole and a low-mass → main sequence  → companion star in orbit around one another. It is thought that SXTs arise in a similar manner to → dwarf novae, through instabilities in the → accretion disk around the → compact object (→ disk instability model).

soft; → X-ray; → transient..

soft X-rays
  پرتوهای ِ ایکس ِ نرم   
partowhâ-ye iks-e narm

Fr.: rayons X mous   

X-ray photons with energies between about 0.1 to 10 keV. → hard X-rays.

soft; → X-rays.

narm-afzâr (#)

Fr.: logiciel   

A general term used to describe a collection of computer programs, procedures, and documentation that perform some tasks on a computer system. → hardware.

soft + ware, from M.E., from O.E. waru, from P.Gmc. *waro (cf. Swed. vara, Dan. vare, M.Du. were, Du. waar, Ger. Ware "goods").

Narm, → soft + afzâr "instrument, means, tool," from Mid.Pers. afzâr, abzâr, awzâr "instrument, means," Proto-Iranian *abi-cāra- or *upa-cāra-, from cāra-, cf. Av. cārā- "instrument, device, means" (Mid.Pers. câr, cârag "means, remedy;" loaned into Arm. aucar, aucan "instrument, remedy;" Mod.Pers. câré "remedy, cure, help"), from kar- "to do, make, build;" kərənaoiti "he makes" (Pers. kardan, kard- "to do, to make"); cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make").

software architecture
  مهرازیک ِ نرم‌افزار   
mehrâzik-e narm-afzâr

Fr.: architecture de logiciel   

The overall structure of a software system consisting of mutually dependent components that create a logical whole.

software; → architecture.

xâk (#)

Fr.: terre, sol   

All loose, unconsolidated earth and organic materials above bedrock that support plant growth.

M.E. soile, O.Fr. soil "piece of ground, place," from L. solium "seat," meaning confused with that of L. solum "soil, ground."

Xâk, from Mid.Pers. xâk "earth, dust," ultimately from Proto-Ir. *āika-, from *āi- "earth, soil," cf. Av. āi- "earth, soil," Gk. aia "earth, land," + suffix -ka. The initial x- is a prothesis, as in xâya "egg" (Gershevitch 1962).


Fr.: jour solaire martien   

The solar day on Mars, which has a mean period of 24 hours 39 minutes 35.244 seconds (based on SI units), about 2.7% longer than Earth's solar day. The Martian sidereal day, as measured with respect to the fixed stars, is 24h 37m 22.663s, as compared with 23h 56m 04.0905s for Earth.

Sol, from L. sol "sun," cognate with Pers. hur, → Sun.

xoršidi (#)

Fr.: solaire   

Of or pertaining to the Sun.

Adjective from L. sol; → Sun.

solar abundance
  فراوانی ِ خورشیدی   
farâvâni-ye xoršidi

Fr.: abondance solaire   

solar photospheric abundance, → solar system abundance.

solar; → abundance.

solar activity
  ژیرندگی ِ خورشید   
žirandegi-ye xoršid

Fr.: activité solaire   

The general term for all forms of short-lived phenomena on the Sun, including → solar flares, → sunspots, → prominences, etc., indicating that the Sun is an active star.

solar; → activity.

solar activity cycle
  چرخه‌ی ِ ژیرندگی ِ خورشید   
carxe-ye žirandegi-ye xoršid

Fr.: cycle d'activité solaire   

Same as the → solar cycle.

solar activity; → cycle.

solar analog
  آناگوی ِ خورشید   
ânâgu-ye xoršid

Fr.: analogue du soleil   

A member of a class of unevolved or slightly evolved → Population I disk stars with an → effective temperature, degree of evolution, → metallicity, and kinematic property not very different from those of the Sun. See also → solar-like star; → solar twin.

solar; → analogue.

solar antapex
  پادچکاد خورشیدی   
pâdcakâd-e xoršidi

Fr.: antiapex solaire   

The apparent direction (in the constellation → Columbia) away from which the Sun is moving in its orbit around the center of the Galaxy. → solar apex.

solar; → antapex.

solar apex
  چکاد ِ خورشیدی   
cakâd-e xoršidi

Fr.: apex solaire   

The point on the celestial sphere toward which the Sun is apparently moving relative to the → local standard of rest. Its position, in the constellation → Hercules, is approximately R.A. 18h, Dec. +30°, close to the star → Vega. The velocity of this motion is estimated to be about 19.4 km/sec (about 4. AU/year). As a result of this motion, stars seem to be converging toward a point in the opposite direction, the → solar antapex.

solar; → apex.

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