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

The force that causes immersed bodies to float or rise to the surface of a liquid or upward in a gas. Buoyant force is produced by → gravity and density differences. Same as → buoyancy.

From buoy (current meaning) "a float moored in water to mark a location," from M.E. boye, from O.Fr. buie or M.Du. boeye, from L. boia "fetter, chain" + suffix -ant; → force.

1) (v.intr.) To undergo combustion (fast or slow).
To undergo fusion or fission.
2) (v.tr.) To cause to undergo combustion.
To use as fuel or as a source of heat.

Burn, from M.E. bernen, brennen, combination of O.E. beornan (intr.) and bærnan (tr.), both from P.Gmc. *brenwanan; cf. Goth. brannjan, O.H.G. brennen.

Suxtan, suzândan, from Mid.Pers. sôxtan, sôzidan "to burn;" Av. base saoc- "to burn, inflame" sūcā "brilliance," upa.suxta- "inflamed;" cf. Skt. śoc- "to light, glow, burn," śocati "burns," (caus.) socayati, śuc- "flame, glow," śoka- "light, flame;" PIE base *(s)keuk- "to shine."

The state, process, or effect of being on fire, burned, or subjected to intense heat. → helium burning; → neon burning; → oxygen burning; → shell burning.

Verbal noun of → burn.

A piece of glass of roundish shape, possibly made of rock crystals or a globular container filled with water, whose use is attested in ancient civilizations. In his comedy The Clouds, the Greek playwright Aristophanes (448-380 BC) mentions globules of glass that were known as burning spheres. Several Roman writers (Pliny, Seneca, Plutarch) speak of burning glasses. In particular, Seneca specifies that small and indistinct written characters appear larger and clearer when viewed through a globular glass filled with water. See also → magnifying glass.

→ burning; → sphere.

Guy, → globe; suzân "burning," → burning.

1a) General: An abrupt, intense increase. A period of intense activity. A sudden outbreak or outburst. An explosion.
1b) Astro.: A period of abrupt increase in the intensity of a phenomenon, for example → star formation rate or emission of radiation such as → X-ray burst, → gamma-ray burst, or → cosmic-ray burst. See also → burst of star formation, → starburst galaxy.
2) To come open or fly apart suddenly or violently, especially from internal pressure.

M.E. bersten, from O.E. berstan, akin to O.H.G. berstan "to burst;" from PIE *bhres- "to burst, break, crack."

1) Belk, Mod.Pers. "a blaze, a flame." The term has several variants, including in dialects: balk [Mo'in], pâlk (Tokharian AB), bal (Gilaki, Semnâni, Sorxeyi, Sangesari, Lahijâni), val (Gilaki), bilese (Kordi), beleyz (Lori), warq, barx [Mo'in], and the Pers. widespread term gorr "burst of fire." Belk derives probably from Mid.Pers. brâh, Av. braz- "to shine, gleam, flash, radiate," cf. Skt. bhâ- "to shine," bhrajate "shines, glitters," O.H.G. beraht "bright," O.E. beorht "bright;" PIE *bhereg- "to shine." The Mod.Pers. barq "glitter; → electricity" probably belongs to this family. Therefore, the Hebrew barak and Ar. barq may be loanwords from Old or Mid.Pers.
2) Belkidan, from belk + infinitive suffix -idan.

A → source that shows sudden intense → emission of → X-rays or → gamma rays with a rapid rise and decay. Often it cannot be identified with any → optical counterpart.

From → burst + -er a noun-forming suffix.

Belkvar, from belk, → burst, + agent noun suffix -var.

A graph on which the latitudes of → sunspots are plotted against time. It shows how sunspots migrate from high latitudes (30°- 40° north or south) to the solar equator (latitude of about 5°) during each → solar cycle, according to → Sporer's law. The shape of these distributions, when represented for both hemispheres, resembles the wings of a butterfly. The diagram was first created by Edward W. Maunder in 1904 to illustrate the solar cycle (M.S.: SDE).

Butterfly, from M.E. butterflye, from O.E. butorfleoge, from butor, butere "butter" floge "fly," but the etymology is not clear; → diagram.

Nemudâr, → diagram; parvânevâr "resembling a butterfly," from parvâné "butterfly" + -vâr similarity suffix.

1) Either of the two large fleshy masses of thick muscular tissue that form the human rump.
2) In animals, the → rump (Dictionary.com).

M.E. buttok, maybe from O.E. buttuc "end; end piece; short piece of land."

Sorin, variant sarun; Mid.Pers. sarinak, srinak (Sogdian šun / šôn "hip, haunch"); Av. sraoni- "buttok, hip;" Skt. śroni- "the hip and loins," Pali soni- "the buttock."

A preposition used to indicate the agent after a passive verb. By means of.

M.E., O.E. bi "near, in, by, during, about;" cf. O.S. and O.Fr. bi, M.Du., Du. bij, Ger. bei;cf. Skt. abhi "toward, to," Gk. amphi- "around, about;" Av. aibi, aiwi, O.Pers. aiby, Pers. af-.

Pat, from Mid.Pers. pat, pad "to, at, in, on" (Mod.Pers. bé); O.Pers. patiy, Av. paiti "to, at, for, with, by mean of," cf. Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti.

Because of a lack of opposition or alternative.

→ by; → default.

A → Be star with → forbidden lines in emission in its spectrum. B[e] stars show large → infrared excess due to → circumstellar dust emission. See also → supergiant B[e] star, → pre-main sequence B[e] star, → compact planetary nebula B[e] star, → symbiotic B[e] star, and → unclassified B[e] star.

B, referring to the spectral type; e for emission lines, brackets for distinction from Be; → star.

Same as → 42 Orionis.

Star name in the → Bayer designation scheme.

One of → Saturn's rings, lying beyond the → D ring and before the → B ring, at 74,658 km from the center of Saturn, with a width of 17,500 km. Same as the → Crepe ring.

→ ring.

Same as → charge conjugation and → charge symmetry.

→ charge; → symmetry.

An → asteroid that belongs to the family of → carbonaceous asteroids. They are → depleted in → hydrogen and → helium, have chemical ratios akin to solar composition, and show low → albedo (0.03-0.09). C-type asteroids are the most common variety, forming around 75% of known asteroids. They inhabit → main belt's outer regions.

C stands for → carbonaceous; → type; → asteroid.

The Sculptor's Chisel. A small inconspicuous → constellation in the southern sky, representing a sculptor's chisel. Its brightest star, Alpha Caeli, is magnitude 4.5. Approximate position: R.A. 4.5 h, Dec.: -40°; abbreviation: Cae, genitive form Caeli.

L. caelum sculptor's "chisel."

Qalam "chisel," from Ar., related to L. caelum?

1) An enclosure, usually made with bars or wire, for keeping birds or wild animals.
2) An enclosed structure resembling a cage. → observer's cage, → Faraday cage.

M.E. from O.Fr. cage, from L. cavea "hollow place, enclosure for animals," cognate with Pers. kâv "hollow," → concave.

Qafas "cage," of unknown origin.

A member of a group of tiny (millimeter to centimeter) light-colored meteorites found often with → chondrules. They consist of high vaporization minerals, including → silicates and → oxides of Ca, Al, and Ti, but are quite poor in Fe. Compared to common → chondrules, which are uniformly spherical, their shapes are less regular. They appear to be 2-3 million years older than chondrules. CAI meteorites are probably the oldest solid materials to have formed in the → solar nebula.

CAI, short for → Calcium, → Aluminium, and → Inclusion; → meteorite.

The standard model of → radiation-driven winds in which the acceleration of → stellar wind is provided by the → absorption and → scattering of ultraviolet photons in ions of abundant elements (→ CNO, → iron peak) in the → Lyman continuum. The model was developed by Castor et al. (1975), who assumed that the forces due to the radiative lines and the pressure gradients are functions of local velocity gradient, and used a large number (~ 10⁵) of lines which have a statistical distribution in line strengths. The model led to predictions of → mass loss rates (M_dot) and terminal velocities as a function of stellar properties and the line statistics parameters. With the modifications by Friend and Abbott (1986), Pauldrach et al. (1986), and Kudritzki et al. (1989), CAK multi-line theory gives good agreement with observationally derived values of mass loss rate and → terminal velocity (v_∞). CAK wind solutions predict the terminal velocity to be proportional to the → escape velocity and the mass loss rate to depend strongly on the stellar → luminosity. Observations over the past decades have shown that these main wind parameters, M_dot and v_∞, indeed behave as predicted by CAK. This basic agreement between observations and theory provides strong evidence that the winds from → massive stars are driven by → radiation pressure and this has favored the CAK formalism. See also → multiple scattering. See the review by J. Puls et al. 2008, Astron. Astrophys. Rev. 16, 209.

CAK, the initials of the researchers who developed the model: J.I. Castor, D.C. Abbott, and R.I. Klein(1975, Radiation-driven winds in Of stars, ApJ 195, 157); → model.

A → bipolar nebula and → OH/IR source with technical designation OH 231.8+4.2. It is a → proto-planetary nebula (PPN) 1.4 → light-years long and located some 5,000 light-years from Earth in the constellation → Puppis. The obscured → central star, named QX Pup, is classified as M9-10 III and has a → Mira-like variability consistent with an evolved → asymptotic giant branch (AGB) star. The late evolution of this object may have been complex since it has a binary → companion star (of type A0 V) that has been indirectly identified from analysis of the spectrum of the hidden central source reflected by the nebular dust. The system has a total luminosity of ~ 10⁴ Lsun and its systemic velocity relative to the → Local Standard of Rest is V_LSR ~ 34 km s^-1. OH 231.8+4.2 is very likely a member of the → open cluster M46 with a progenitor mass of ~ 3 Msun. The nebula is also known as the Rotten Egg Nebula because it contains a lot of sulphur, an element that, when combined with other elements, smells like a rotten egg (see, e.g., Prieto et al., 2015, A&A, 575, A84).

The name "Calabash Nebula" was first proposed by Icke & Preston, 1989, A&A, 211, 409. It refers to the apparent form of the object which resembles a calabash "a tree that has large, rounded gourdlike fruit; the fruit of any of these plants," from Sp. calabaza, possibly from Ar. qar'ah yâbisah "dry gourd," from Pers. kharabuz, used of various large melons; → nebula.