An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -sc Sag sam sat sca sca Sch Sco sec sec sec seg sel sem sep set sha she sho sid sig sil sim sin siz sle smo soc sol sol sol sol sol sou spa spa spe spe spe sph spi spi spr sta sta sta sta sta ste ste sto str str str sub sub sub Sun sup sup sup sup sur swa sym syn > >>

Number of Results: 1316

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.

solar axial tilt
  گرای ِ آسه‌ی ِ خورشید   
gerâ-ye âse-ye xoršid

Fr.: inclinaison de l'axe du Soleil   

The angle between the Sun's → rotation axis and perpendicular to the → ecliptic plane. In other words, the inclination of the Sun's → equator with respect to the → ecliptic plane. It is 7.25 degrees.

solar; → axial; → tilt.

solar calendar
  گاهشمار ِ خورشیدی   
gâhšomâr-e xoršidi (#)

Fr.: calendrier solaire   

A calendar based on the apparent yearly motion of the Sun on the → celestial sphere. The year is usually reckoned with respect to the → vernal equinox, approximately for example in the case of the → Gregorian calendar and accurately in the case of the → Iranian calendar.

solar; → calendar.

solar constant
  پایای ِ خورشیدی   
pâypa-ye xoršidi (#)

Fr.: constante solaire   

The amount of solar radiation in all wavelengths received per unit of time per unit of area on a theoretical surface perpendicular to the Sun's rays and at Earth's mean distance from the Sun. Its mean value is 1367.7 W m-2 or 1.37 × 106 erg sec-1 cm-2. In other words, the solar constant is the mean → solar irradiance on the outer atmosphere when the Sun and Earth are spaced at 1 → astronomical unit. See also: → solar luminosity.

solar; → constant.

solar corona
  هورتاج، تاج ِ خورشیدی   
hurtâj, tâj-e xoršid (#)

Fr.: couronne solaire   

The outermost atmosphere of the Sun immediately above the → chromosphere, which can be seen during a total solar eclipse. It consists of hot (1-2 × 106 K), extremely tenuous gas (about 10-16 g cm-3) extending for millions of kilometer from the Sun's surface.

solar; → corona.

solar cycle
  چرخه‌ی ِ خورشیدی   
carxe-ye xoršidi (#)

Fr.: cycle solaire   

The periodic variation in frequency or number of solar active events (→ sunspots, → prominences, → flares, and other solar activity) occurring with an interval of about 11 years. The solar cycle was discovered in 1843 by Samuel Heinrich Schwabe (1789-1875), a German apothecary and amateur astronomer, who after 17 years of observations noticed a periodic variation in the average number of sunspots seen from year to year on the solar disk. Solar cycle numbering goes back to the 18-th century, when the Cycle 1 peak occurred in 1760. Cycle 23 peaked in 2000, and the following Cycle 24 will reach its maximum in 2013.

solar; → cycle.

solar day
  روز ِ خورشیدی   
ruz-e xoršidi (#)

Fr.: jour solaire   

The length of time between two successive transits of the Sun over the same meridian.

solar; → day.

solar depression
  نشیب ِ خورشید   
nešib-e xoršid

Fr.: dépression solaire   

The → angle between the → sea horizon, the → center of → Earth, and the center of the → solar disk.

solar; → depression.

solar disk
  گرده‌ی ِ خورشید   
gerde-ye xoršid

Fr.: disque solaire   

The apparent shape of the → Sun's → photosphere.

solar; → disk.

solar dynamo
  توانزای ِ خورشیدی   
tavânzâ-ye xoršidi (#)

Fr.: dynamo solaire   

A model for explaining the generation of the → solar magnetic field and the related observational features (mainly → solar cycle, → Sporer's law, → Hale's law, → Joy's law, → polarity reversal). The global frame of this model is the interaction between a → turbulent plasma in the → convective zone (reciprocal generation of magnetic and electric fields) and the solar differential rotation (mutual transformation of meridional magnetic field into azimuthal magnetic field). The idea that a dynamo is responsible for generating the solar magnetic field was first proposed by Larmor (1919) and further developed by Cowling (1933), Parker (1955) and others.

solar; → dynamo.

solar eclipse
  خورگرفت، گرفت ِ خورشیدی   
xor gereft, gereft-e xoršidi (#)

Fr.: éclipse de soleil   

An eclipse in which the Earth passes through the shadow cast by the Moon. Solar eclipses only happen when the Moon is new and when the Moon lies close to the node of its orbit.

solar; → eclipse.

solar ecliptic limit
  حد ِ هورپهی ِ خورشید   
hadd-e hurpehi-ye xoršid

Fr.: limite écliptique du Soleil   

The greatest angular distance from a → lunar orbit node within which a → solar eclipse may occur when the Sun and Moon are in conjunction there. The solar ecliptic limit extends about 17° on each side of the node.

solar; → ecliptic; → limit.

solar equation
  هموگش ِ خورشیدی   
hamugeš-e xoršidi

Fr.: équation solaire   

In ancient astronomy, the difference between the Sun's mean and actual position. The ancients observed that, although the motion of the Sun in the ecliptic is almost uniform, it is subject to a small annual variation.

solar; → equation.

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