An Etymological Dictionary of Astronomy and Astrophysics
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One of the three quantities (k, α, and δ) which are used in the → radiation-driven wind theory to express the radiation pressure due to spectral lines. These coefficients parametrize the radiation acceleration as: g_rad≅ k(dv/dr)^αg_e, where g_e = σ_eL/4πcR_*² is the radiative acceleration by electron scattering. The parameter k is dependent on the number of lines that produce the radiation pressure. The parameter α depends on the optical depth of the driving lines and varies between 0 (optically thin) and 1 (optically thick). The parameter δ describes the dependence of k on the density with k ≅ ρ^δ. The velocity law of radiation-driven winds depends on α and δ, but not on k. The → mass loss rate depends on k, α, and δ (Castor et al. 1975, ApJ 195, 157; Lamers et al., 1995, ApJ 455, 269 and references therein).

→ force; → multiplier; → parameter.

Math.: A constant that appears in the process for obtaining extrema of functions of several variables. Suppose that the function f(x,y) has to be maximized by choice of x and y subject to the constraint that g(x,y)≤ k. The solution can be found by constructing the → Lagrangian function  L(x,y,λ) = f(x,y) + λ[k - g(x,y)], where λ is the Lagrangian multiplier.

→ Lagrangian point; → multiplier.

Of two or more → integers, the smallest positive number that is divisible by those integers without a remainder.

→ least; → common; → multiplier.

Arithmetic: A number by which another is multiplied. Physics: A device for intensifying some effect.

Agent noun of → multiply.

Electronic tube which converts photons into electrons, multiplies the electrons via a series of electrodes, and produces a measurable current from a very small input signal.

→ photo- + → multiplier.