effective temperature


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effective temperature

Symbol T eff, T e. The surface temperature of a star, expressed as the temperature of a black body (i.e. a perfect radiator) having the same radius as the star and radiating the same total amount of energy (E) per unit area per second. A star is thus being considered a black body and its effective temperature is thus given by Stefan's law:
T eff 4 = E /σ = L /4πR 2

σ is Stefan's constant and L and R are the star's luminosity and radius. Although accurate determinations of effective temperature are difficult, each spectral type has a characteristic range of T eff; the total range is from about 2500 to over 40 000 kelvin. The Sun's effective temperature is 5770 K. The effective temperature is the best measure of the actual temperature of the gas in a star's outer layers.

Radiation temperature, T r, is equivalent to the effective temperature measured not over the whole spectral range but over a narrow portion of the spectrum, for example at visible wavelengths, which gives the optical temperature.

effective temperature

[ə¦fek·tiv ′tem·prə·chər]
(astrophysics)
A measure of the temperature of a star, deduced by means of the Stefan-Boltzmann law, from the total energy that is emitted per unit area.
(meteorology)
The temperature at which motionless, saturated air would induce, in a sedentary worker wearing ordinary indoor clothing, the same sensation of comfort as that induced by the actual conditions of temperature, humidity, and air movement.
(statistical mechanics)
That temperature which can be inserted in the Boltzmann distribution formula to describe the relative populations of two energy levels which may or may not be in thermal equilibrium.

effective temperature

An index which combines into a single figure the effects of temperature, humidity, and air movement on the sensation of warmth or cold felt by the human body; numerically equal to the temperature of still, saturated air which induces an identical sensation.
References in periodicals archive ?
Changes in the LBVs' effective temperature and radius during an S Dor cycle are typically calculated by assuming a constant bolometric luminosity (e.g., [20]).
The minimum effective temperature of bridge deck, main cable, and air is almost the same, while the maximum effective temperature of bridge deckis significantly higher.
Matsubara, "Conduction-corrected modified effective temperature as the indices of combined and separate effect of environmental factors on sensational temperature," Energy and Buildings, vol.
The 95% confidence intervals of the difference between any 2 sums of effective temperatures based on bootstrap percentiles are:
If the oceans had been able to emit with an effective temperature near 300 K, they would be expected to produce an extensive radiation in the microwave region of the electromagnetic spectrum.
[T.sub.amb] = the effective temperature of the object surroundings or the reflected ambient temperature
Effective temperature control of the surface can only be achieved through accurate non-contact temperature measurement, according to the literature.
Evaporative cooling delivers an effective temperature to 80 E Reducing ambient temperature around injection molds reduces sweat.
The TK Data Logger range is made up from the TKDL-PRO, a high performance printing data logger with temperature alarm monitoring and a high speed offload of recorded data, the TKDL-SPR, a simple and cost effective temperature data logger for the small vehicle / home delivery service sector and the TKDL-DCS, an automatic Data Capture System for refrigerated vehicles with a twelve month memory as standard.
These measuring values represent the actually effective temperature gradient of the welding process surrounding.
Maximized to operate at lower rpm's, this new fan produces more cfm per watt, and can be sped up to produce 332,000 cfm to lower the effective temperature in warehouses, plants, and commercial facilities.
Featuring built-in cold junction compensation (CJC), the EL041 has an effective temperature range of -250[degrees]C to 1,820[degrees]C (using thermocouple types B, E, J, K, N, R, S and T), is accurate to 0.3 percent [+ or -]0.5[degrees]C and has a resolution of better than 0.2[degrees]C.

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