# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 14 Search : minimum
 angle of minimum deviation   زاویه‌ی ِ کژرفت ِ کمینه   zâviye-ye kažraft kaminéFr.: angle de déviation minimale   The angle between the light entering and exiting the prism when the light passing through the prism is parallel to the prism's base. Angle of minimum deviation (D) is used to measure the → index of refraction (n) of the prism glass, because: n = sin [(A + D)/2]/sin (A/2), where A is the → prism angle.→ angle; → minimum; → deviation. Dalton minimum   کمینه‌ی ِ دالتون   kamine-ye DaltonFr.: minimum de Dalton   A 40-year period of unusually low → solar activity, from about 1790 to 1830. See also the → Maunder minimum.Named after John Dalton (1766-1844), British meteorologist; → minimum. local minimum   کمینه‌ی ِ محلی   kamine-ye mahaliFr.: minimum local   The point x = c in an → interval where the value of the → function  f(y) is smaller than the value anywhere else in that interval. In other words, f(c) ≤ f(x) for all x in the interval.→ local; → minimum. Maunder minimum   کمینه‌ی ِ ماؤندر   kamine-ye MaunderFr.: minimum de Maunder   A period from about 1645 to 1715 when the number of → sunspots was unusually low. This → solar activity minimum is attested also through the increased content of carbon 14 in tree rings in that period. The reason is that the cosmic rays which produce 14C reach the Earth in a greater number when there is weak solar activity (see also → radiocarbon dating). The Maunder minimum occurred during a period of cooling of the Earth, called the → Little Ice Age. The Maunder minimum is one of a number of periods of low solar activity, including the → Dalton minimum, the → Sporer minimum, the → Wolf minimum, and the → Oort minimum.After the British astronomer Edward Walter Maunder (1851-1928) who, along with Gustav Spörer of Germany, first called attention to this phenomenon; → minimum. minimum   کمینه   kaminé (#)Fr.: minimum   The least value attained (or attainable) by a function; the opposite of maximum.From L. minimum "smallest" (thing), neuter of minimus "smallest," superlative of → minor "smaller."Kaminé, from kamin superlative of kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few." Keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + -é nuance suffix. minimum deviation   کژرفت ِ کمینه   kažraft-e kaminéFr.: déviation minimale   Same as → angle of minimum deviation.→ minimum; → deviation. minimum orbit intersection distance (MOID)   دورای کمینه‌ی ِ اندرسکنج ِ مدار   durâ-ye kamine-ye andarsekanj-e madârFr.: distance minimale d'intersection d'une orbite   The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.→ minimum; → orbit; → intersection; → distance. minimum stellar mass   جرم ِ کمینه‌ی ِ ستاره   jerm-e kamine-ye setâreFr.: masse stellaire minimum   The amount of hydrogen necessary to form a star; more specifically the minimum mass to ignite → hydrogen fusion. → Hydrogen burning will start at a limit of about 0.08 Msun, or 75 → Jupiter masses. Below 0.08 Msun, the core never gets hot enough to trigger → hydrogen fusion. → Protostars less massive than this limit are known as → brown dwarfs or → planets if the mass is less than 13 Jupiter masses. Above 13 Jupiter masses, some minor nuclear reactions (→ deuterium burning) occur that do not provide much energy. The minimum mass for → star formation is a critical parameter with profound astrophysical, cosmological, and even anthropic consequences.→ minimum; → stellar; → mass. Oort minimum   کمینه‌ی ِ اورت   kamine-ye OortFr.: minimum de Oort   A 40-year period of unusually low → solar activity, from about 1010 to 1050. See also the → Maunder minimum.→ Oort cloud; → minimum. solar minimum   کمینه‌ی ِ خورشیدی   kamine-ye xoršidiFr.: minimum solaire   The month(s) during the 11 year → solar cycle when the number of → sunspots is lowest.→ solar; → minimum. Spörer minimum   کمینه‌ی ِ اشپورر   kamine-ye SpörerFr.: minimum de Spörer   A period of low → solar activity that lasted from about A.D. 1420 to 1570. It occurred before → sunspots had been studied, and was discovered by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity.Named for the German astronomer Gustav Spörer (1822-1895); → minimum. Sporer minimum   کمینه‌ی ِ اشپورر   kamine-ye SpörerFr.: minimum de Spörer   A period of low → solar activity that lasted from about A.D. 1420 to 1570. It occurred before → sunspots had been studied, and was discovered by analysis of the proportion of carbon-14 in tree rings, which is strongly correlated with solar activity.Named for the German astronomer Gustav Spörer (1822-1895); → minimum. sunspot minimum   کمینه‌ی ِ هورلک   kamine-ye hurlakFr.: minimum des taches   Periods of time when the → relative sunspot number is low. These periods of time occur approximately every 11 years and represent the minimum in the → sunspot cycle.→ sunspot; → minimum. Wolf minimum   کمینه‌ی ِ ولف   kamine-ye WolfFr.: minimum de Wolf   A 70-year period of unusually low → solar activity, from about 1280 to 1350. See also the → Maunder minimum.→ Wolf number; → minimum.