An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < abs app Lar res sol sol sol sol X-r > >>

Number of Results: 161 Search : sol
Larson-Penston solution
  لویش ِ لرسون-پنستون   
luyeš-e Larson-Penston

Fr.: solution de Larson-Penston   

The analytical solution to the → hydrodynamic equations describing the → collapse of an → isothermal sphere. The Larson-Penston solution is → self-similar for a purely dynamical isothermal collapse with spherical symmetry. It corresponds to the collapse prior to the formation of a → protostar, and thus is suitable for the study of → pre-stellar cores. The Larson-Penston solution was extended by Shu (1977) to obtain a whole family of solutions for this problem.

Named after R. B. Larson (1969, MNRAS 145, 271) and M. V. Penston (1969, MNRAS 144, 425), who simultaneously, but independently, did this study.

low resolution
keh vâgošud

Fr.: faible résolution   

The quality of an instrument that lacks sufficient resolution for a specific observation. This is a relative quality, but presently a resolution below about 1 arcsecond.

low; → resolution.

lunisolar calendar
  گاهشمار ِ مانگی-خورشیدی   
gâhšomâr-e mângi-xoršidi

Fr.: calendrier luni-solaire   

A calendar in which the → solar year consists of 12 or 13 lunar → synodic months. Lunisolar calendars are → solar calendars, but use the lunar month as the basic unit rather than the → solar day. The 13th → embolismic month is to keep lunar and solar cycles in pace with each other. The reason is that the solar year has about 365 days, but 12 lunar months amount to 354 days, which is about 11 days short of a year. The most well-known lunisolar calendars are the Babylonian, Hebrew, and Chinese.

From luni-, from → lunar, + → solar; → calendar.

lunisolar precession
  پیشایان ِ مانگی-خورشیدی   
pišâyân-e mângi-xorši

Fr.: précession lunisolaire   

precession of the equator.

From luni-, from → lunar, + → solar; → precession.

mean solar day
  روز ِ خورشیدی ِ میانگین   
ruz-e xoršidi-ye miyângin (#)

Fr.: jour solaire moyen   

The average length of the apparent solar day. In other words, the interval between successive transits of the mean Sun for a given observer.

mean; → solar; → day.

mean solar time
  زمان ِ خورشیدی ِ میانگین   
zamân-e xoršidi-ye miyângin (#)

Fr.: temps solaire moyen   

The time since the mean Sun crossed the meridian with 12 hours added to make the day begin at midnight.

mean; → solar; → time.

  پیتاری، پیتارستی   
pitâri, pitâresti

Fr.: obsolescence   

The state, process, or condition of being or becoming obsolete or outdated and no longer used.

obsolete; → -escence.

  پیتارشو، پیتارست   
pitâršo, pitârest

Fr.: obsolescent   

Becoming obsolete; passing out of use.

obsolete; → -escent.

  ۱) پیتار؛ ۲) پیتاردن   
1) pitâr; 2) pitârdan

Fr.: 1) obsolète, désuet; 2) rendre obsolète   

1a) No longer in general use; fallen into disuse.
1b) Biology: (of a living organism) Reduced to a redument, or completely lacking, as compared with a corresponding part in related organisms.
2) To make obsolete by replacing with something newer or better.

From L. obsoletus "grown old, worn-out," p.p. of obsolescere "fall into disuse, be forgotten about, become tarnished," which probably is from ob "away" + an expanded form of solere "to be used to, be accustomed."

Pitâr, from Tabari pitâr "worn out," specifically "rotten tree," pitə-pât "anything worn out or useless," from pit, variant of Pers. pud "worn out, decayed," pusidan/pus- "to rot," cf. Pashto puda, Wakhi pitk "rotten, foul," Kurd. (Kurm.) puc "rotten, useless;" Av. pu- "to stink, rot," akin to Gk. puos, L. pus "pus."

Parker Solar Probe
  گمانه‌ی ِ خورشیدی ِ پارکر   
gomâne-ye xoršidi-ye Parker

Fr.: Parker Solar Probe   

A NASA space mission launched on August 12, 2018 to study the outer corona of the Sun at very close distances. Parker Solar Probe is the first space mission to penetrate into solar corona as close as about 10 solar radii. It will approach the Sun to this distance 25 times. Approaching the Sun to such distances is a big technological challenge. The main goals of the mission are to answer these questions: Why is the solar corona so hotter than the solar surface? How is the solar wind accelerated? How are the energetic particles produced and transported?

Named after the physicist Eugene Newman Parker (1927-), who proposed the existence of the solar wind and did pioneering work for its interpretation.

partial solar eclipse
  خورگرفت ِ پاری   
xorgereft-e pâri

Fr.: éclipse partielle de soleil   

A → solar eclipse when only the → penumbra of the Moon touches the Earth. The → umbra passes either just above the North Pole or just below the South Pole, missing the Earth.

partial; → solar; → eclipse.

particular solution
  لویش ِ پارولی   
luyeš-e pâruli

Fr.: solution particulière   

Of partial differential equations, the solution which can be obtained from the general solution by particular choice of the arbitrary functions. → general solution; → singular solution.

particular; → solution.

planned obsolescence
  پیتاری ِ پیشگاشته   
pitâri-ye pišgâšté

Fr.: obsolescence programmée   

The business strategy of deliberately designing products so they have a limited effective lifespan. Its objective is to incite the consumer to abandon the currently owned item and buy another one.

Planned, p.p. of "to → plan;" → obsolescence.


Fr.: pré-solaire   

Of or relating to an epoch earlier than the formation of the Sun.

pre-; → solar.

presolar grain
  دانه‌ی ِ پیش-خورشیدی   
dâne-ye piš-xoršidi

Fr.: grain pré-solaire   

A → refractory → nanoparticle embedded in → meteorites and → interplanetary dust particles whose → isotopic ratios suggest formation earlier than the Solar System.

presolar; → grain.


Fr.: protosolaire   

Describing the conditions prior to the formation of the → solar system, or pertaining to the → protostar that became the → Sun.

proto- + → solar.

protosolar abundance
  فراوانی ِ پوروا-خورشیدی   
farâvâni-ye purvâ-xoršidi

Fr.: abondance protosolaire   

The abundance of a chemical element pertaining to the proto-→ solar nebula from which the → solar system was formed. → CI chondrite; → CAI meteorite.

protosolar; → abundance.


Fr.: résolution   

1) The degree to which an → optical system renders visible separate parts of an object. Also known as → angular resolution and → spatial resolution. See also → spectral resolution.
2) The time interval between successive discernible signals. → temporal resolution.

Verbal noun of → resolve.

resolution of a force
  واگشود ِ نیرو   
vâgošud-e niru

Fr.: résolution de force   

Finding the → components of a → force which act in specified → directions.

resolution; → force.


Fr.: résoudre   

To separate and make visible the individual parts of an → image or → spectral feature.

M.E. resolven, from L. resolvere "to loosen, undo, settle," from → re- + solvere "to loosen," → solve.

Vâgošudan, from prefix vâ-, → re-, + gošudan, gošâdan "to loose, open up, let free;" gošâd "opened; ample, broad;" Mid.Pers. wišâdan "to let free;" Khotanese hīyā "bound;" O.Pers. višta "untied, loosened," vištāspa- "with loosened horses" (personal name); Av. višta "untied," ā-hišāiiā "holds fettered," hita- "fastened, tied on, put to;" cf. Skt. sā- "to bind, fasten, fetter," sitá- "bound," ví-sita- "untied."

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