An Etymological Dictionary of Astronomy and Astrophysics
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A non-variable star used to monitor the variations of another nearby star.

→ comparison; → star.

1) The act of competing; rivalry for supremacy, a prize, etc. 2) A contest for some prize, honor, or advantage (Dictionary.com).

Verbal noun of → compete + → -tion.

A scenario for → massive star formation whereby developing → protostars in their natal → molecular clouds compete with each other to gather mass. The protostars → accrete mass with a rate which depends on their location within the protocluster. They use the same reservoir of gas to grow. Therefore those protostars nearest the center, where the potential well is deep, and gas densities are higher, have the highest → accretion rates. The competitive accretion model explains the observational fact that the most massive stars are generally found in cluster cores. It accounts also for the distribution of stellar masses. In this model the accretion process depends on the content of the cluster. In clusters where gas dominates the potential (e.g. at initial stages of cluster formation), the accretion process is better modeled by using the → tidal radius as the accretion radius. In contrast, when the stars dominate the cluster potential and are virialized, the accretion is better modeled by → Bondi-Hoyle accretion (Bonnell et al. 1997, MNRAS 285, 201; 2001, MNRAS 323, 785).

→ competitive; → accretion; → model.

The act of compiling; something compiled.

→ compile; → -tion.

A → complex number in which the → real part of the number remains the same, but i is replaced by -i. For example, the complex conjugate of x + iy is x - iy. Same as → conjugate complex number.

→ complex; → conjugate.

A fraction in which the → numerator or → denominator, or both, contain fractions. For example (3/5)/(6/7). Also called → compound fraction.

→ complex; → fraction.

A function whose → variables are → complex numbers.

→ complex; → function.

Same as → composite population.

→ complex; → population.

A constituent part; an individual part of an organized whole.
One of two or more vectors having a sum equal to a given vector.

L. componentem, pr.p. of componere "to put together," → compose.

Hamneh from ham- "together," → com- + neh present tense stem of nehâdan "to put, place," → compose.

A stellar population consisting of more than one → simple population. Also called complex population.

→ composite; → population.

1) General: The act or manner of composing; the result or product of composing.
2) Chemistry: The proportion of the elements of which a substance is made up.
3) Mechanics: The determination of a force whose effect is the same as that of two or more given forces acting simultaneously.

Hamnehesh, from ham-, → com-, + neheš verbal noun from nehâdan "to put, place," → compose.

Same as → complex fraction.

→ compound; → fraction.

A statement formed from simple statements by the use of words such as "and," "or," "not," "implies," or their corresponding symbols.

→ compound; → proposition.

1) The ability to → comprehend something.
2) In logic, the sum of all the essential attributes which analysis can find in a concept or term. For example, the comprehension of the term man is rational animal; the → extension of the term man, is all men and women. Comprehension and extension are inversely proportional. The greater is the comprehension of a term, the less is its extension.

Verbal noun of → comprehend.

The act or process of compressing; the state of being compressed.

Verbal noun from → compress.

In thermodynamics, the quantity Z = pV_m/RT, in which P is the gas pressure, V_m the molar volume, R the gas constant, and T the temperature. The compression factor is a measure of the deviation of a real gas from an ideal gas. For an ideal gas the compression factor is equal to 1.

→ compression; → facteur.

A → longitudinal wave that compresses the → medium along the direction of → propagation, such as a → sound wave. Same as → compressional wave.

→ compression; → wave.

Of or relating to → compression.

→ compression; → -al.

An → elastic wave that travels through a → medium with the particles of the medium moving in the same direction as the wave propagation. The compressional wave is the wave that is primarily used in → seismic exploration. Also called P-wave, primary wave, pressure wave.

→ compressional; → wave.

The American physicist Arthur Holly Compton (1892-1962), the Nobel Prize in Physics 1927, who made important contributions to the study of X- and cosmic rays.
→ Compton catastrophe, → Compton effect, → Compton equation, → Compton era, → Compton recoil, → Compton scattering, → Compton shift, → Compton suppression, → Compton wavelength, → Comptonization.