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

Any of the chemical elements belonging to group A of the → periodic table, which burn vigorously in air; i.e. → lithium, → sodium, → potassium, → rubidium, → cesium, and → francium. Alkali metals have a → valence of one and are softer and less dense than other metals.

→ alkali; → metal.

Having the properties of an → alkali; having a → pH greater than 7.0.

From alkal(i) + -ine a suffix denoting "of or pertaining to," "of the nature of," "like."

From qalyâ, → alkali, + -yi adj. suffix.

Any of the metallic chemical elements belonging to group 2 of the → periodic table; i.e. → beryllium, → magnesium, → calcium, → strontium, → barium, and → radium. They are not found free in the nature because they are highly reactive.

→ alkaline; → earth; → metal.

Felez, → metal; qalyâyi, → alkaline; xâki "of or pertaining to soil," from xâk, → soil.

The whole quantity or amount.

M.E. al, plural alle; O.E. eall "all, every, entire;" cf. O.Fris., O.H.G. al, O.N. allr, Goth. alls.

Hamé- "all," variant hami "all the time, always;" Mid.Pers. hamâg "all," hamê "all the time, always;" Av. hama- "any;" cf. Skt. sama-"any, every, whichever;" Gk. amo-then "whichever;" Goth. sums "any;" O.N. sumr "any;" O.E. sum "some;" E. some.

A → survey that collects data on the whole sky. For example the infrared → Two Micron All Sky Survey (2MASS) and the X-ray → ROSAT All-Sky Survey.

→ all; → sky; → survey.

A "Large Number of Small Dishes" (LNSD) array designed to be sensitive for → commensal surveys of conventional → radio astronomy projects and → SETI targets at centimeter wavelengths. The ATA will consist of 350 6m-diameter → dishes when completed, which will provide an outstanding survey speed and sensitivity. In addition, the many → antennas and → baseline pairs provide a rich → sampling of the → interferometer  → uv plane, so that a single pointing snapshot of the array of 350 antennas yields an image in a single field with about 15,000 independent → pixels. Other important features of the ATA include continuous frequency coverage over 0.5 GHz to 10 GHz and four simultaneously available 600-MHz bands at the → back-end which can be tuned to different frequencies in the overall band. The ATA is a joint project of the Radio Astronomy Laboratory of the University of California, Berkeley, and the SETI Institute in Mountain View, CA. The ATA is now complete to 42 antennas. Highlights of the system are the frequency agility, the low background and → side lobes of the antennas, the wideband feed and input receiver, the analog fiber optical system, the large spatial dynamic range, the back-end processing systems and the overall low cost (see, e.g., Backer et al., 2009, arXiv:0908.1175.pdf).

Named after Paul G. Allen (1953-2018), an American business magnate, computer programmer, researcher, investor, and philanthropist. A donation of $11.5 million by his foundation in 2004 contributed to the development of the project.

1) The act of allying or state of being allied; the result of this action.
2) A union to advance the common interests of the members.

M.E., from O.Fr. aliance, from al(ier) "to ally," → alloy, + → -ance.

Hamdasti, literally "joining hand," from ham-, → com-, + dast, → hand, + -i noun suffix.

1) General: To assign or allot for a particular purpose.
2) Computers: To assign an amount of resource (disk, memory, CPU time, etc.) to a defined user.

From M.L. allocate imperative plural of allocare "allocate," from → ad- "to" + locare "to place," from locus "a place."

Teskidan, from tesk "portion, share, part, lot; a tax upon lands, tribute extracted," variants tešk, toxs (kardan) "distribute, divide;" loaned in Ar. tisq, tasq; tasu "a weight of four barley corns; the twenty-forth part of a weight;" Mid.Pers. tasû "the fourth part," loaned in Ar. tassûj, in Syriac tassûgâ "the fourth part; a measure;" ultimately Proto-Ir. *caçû-ka-; cf. Av. caθwarô, catur-, → four.

The act of allocating; the state of being allocated.

Verbal noun of → allocate.

One of two or more forms in which a → chemical element occurs, each differing in physical properties; e.g. → diamond and → graphite are allotropes of → carbon.

From allo-, combining form of Gk. allos "other, different;" cf. L. alius "else;" → alias + trope, from Gk. -tropos "a turn, way, manner," from tropein "to turn;" PIE base *trep- "to turn" (cf. L. trepit "he turns").

Degarvâr, from degar "other, another" (Mid.Pers. dit, ditikar "the other, the second;" O.Pers. duvitiya- "second;" Av. daibitya-, bitya- "second;" Skt. dvitiya- "second;" PIE *duitiio- "second") + -vâr denoting "resembling, like;" Mid.Pers. -wâr; Av. -vara, -var; cf. Skt. -vara.

A property of certain → chemical elements, as → carbon, → sulfur, and → phosphorus of existing in two or more distinct forms, known as → allotropes.

→ allotrope.

In solid-state physics, the range of energies which electrons can attain in a material.

P.p. of v. allow, from O.Fr. alouer "approve," from L. allaudare , compound of → ad- "to" + laudare "to praise."

Bând, → band; parzâmidé, p.p. of parzâmidan "to send through, permit, allow," from parzâm "permission," from par- "through" + zâm stem of zâmidan, Mid.Pers. zâmenidan "to send, lead;" → permit

A material composed of two or more → metals, or of a metal or metals with a non-metal, exhibiting characteristic metallic properties. Some examples: → bronze is an alloy of → copper and → tin, brass is an alloy of → zinc and copper, and → steel is an alloy of → iron and → carbon. Alloys have properties which differ from those of their components. Moreover, different component proportions yield alloys with different properties.

From M.F. aloi, from O.Fr. alei, from aleier "to mix, combine," from L. alligare "to bind up," from → ad- "to" + → ligare "to bind."

Âlyâž, loanword from Fr.

The third brightest star in Andromeda and one of the most beautiful double stars in the sky. The brighter star of the pair appears golden yellow or slightly orange; it is a bright (of second magnitude) giant K star. The fainter companion, which appears greenish-blue, is also double.

This star is also known as Almaak, Alamak, Almak, or Almaach, from Ar. Al-'Anaq al-'Ardh "a small animal of Arabia similar to a badger."

A comprehensive treatise, compiled by Claudius Ptolemy of Alexandria, around A.D. 140, that summarized the astronomy, geography, and mathematics of antiquity, and included a star catalogue with data for 1,022 stars.

Almagest, from Ar. Al-majisti, from al "the" + Gk. megiste (suntaxis) "the greatest (composition)," from femenine of megistos, superlative of megas "great."

A book of tables, usually covering a period of one calendar year, that lists the future positions of the Moon, planets, and other prominent celestial objects, together with other useful astronomical data.

M.E. almenak, from M.L. almanach, perhaps from late Gk. almenikhiaka "ephemeris," perhaps of Coptic origin.

Axtar sâlnâmé, from axtar, → star, + sâlnâmé "calendar," from sâl, → year, + nâmé "book."

A small circle on the celestial sphere parallel to the horizon. The locus of all points of a given altitude. Also called altitude circle, circle of altitude, parallel of altitude.

Almucantar, from L. almucantarath, from Ar. almuqantarât, from al- "the" + muqantarât "sundial," from qantarah "arch".

Moqantar, from Ar., as above. Parhun-e farâzâ from parhun, → circle, + farâzâ→ altitude.

A blue star of visual magnitude 1.65 in the constellation → Taurus. Alnath is a giant star of type B7 lying at a distance of about 10.95 → light-years.

Alnath, from Ar. An-nâteh "the butting" (horn), from nath "to butt".

Šâxzan "the butting," from Mod.Pers. šâx zadan "to butt or push with the horns," from šâx "horn" + zadan "to strike, to butt".

The central and brightest of the three stars in → Orion's Belt and the fourth brightest in the whole of → Orion. Alnilam is a blue-white → supergiant of → spectral type B0 Iae with a → visual magnitude of 1.70 and a → luminosity of 375,000 times the → solar luminosity. It lies at about 1,340 → light-years.

Alnilam, from Ar. An-Nizam al-Jawza' (النظام‌الجوزاء) "the Orion's arrangement (of pearls, beads)," from nizam "arrangement" + Jawza' "Orion".

The left hand or easternmost star in → Orion's Belt, which is the fifth brightest in the whole of → Orion with a → visual magnitude of 1.79. Alnitak is a wide visual binary system consisting of components ζ Ori A (HR 1948) and ζ Ori B (HR 1949), currently separated by ~ 2''.4. ζ Ori A is a → close binary system comprising Alnitak Aa and Alnitak Ab. Aa is a hot → blue supergiant of → spectral type O9.5 Iab with an → absolute magnitude of -6.0 and an → apparent magnitude of 2.08. Its mass is estimated as being up to 33 times as massive as the Sun and to have a diameter 20 times greater. It is some 250,000 times more luminous than the Sun, with a surface temperature of about 30,000 K. It is the brightest star of class O in the night sky. Alnitak Ab is a blue → subgiant of spectral type B1 IV with an absolute magnitude of -3.9, an apparent magnitude of 4.3, and a mass of 14 Msun. Ab revolves around Ab with a period of 2,687 days. The system has a 4th magnitude companion, Alnitak B, nearly 3 arc-seconds distant. It is a B0 III type star which orbits Alnitak A every 1,500 years. Alnitak is associated with the → emission nebula  → IC 434 containing the → Horsehead Nebula.A much fainter fourth component, ζ Ori C, is located about 57'' away from ζ Ori Aa (C. A. Hummel et al., 2013, A&A 554, A52, arXiv:1306.0330).

Alnitak, from Ar. An-Nitaq al-Jawza' (النطاق‌الجوزاء) "Orion's Belt," from nitaq "belt" + Jawza "Orion."