The Physics
Factbook
An encyclopedia of scientific essays

Temperature of a "White Hot"Object

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Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Chaisson, Eric and McMillan, Steve. Astronomy Today. New Jersey: Prentice-Hall, 1993.
Stellar Colors and Temperatures
B Intensity
V Intensity
Surface
Temperature (K)
Color Familiar
Examples
1.0 10,000 White Vega, Sirius
0.8 8,000 Yellow-white Canopus
8,000–10,000 K
The Audubon Society–Field Guide to the Night Sky. New York: Knopf.
SPECTRA TYPES
Type Color Temperature
Range (K)
Example
A Blue-white 11,000–75,000[sic] Sirius (Alpha Canis majoris)
F White 6,000–7,500 Procyon (Alpha Canis minoris)
G Yellow-white 5,000–6,000 The Sun
5,000–11,000 K
Process Associates of America. Metal Temperature by Color. 1995–2000.
Metal Temperature by Color
Color °F °C K
White 2200 1205 1480
1,480 K
Pananides, Nicholas A. and Arny, Thomas. Introductory Astronomy. California: Addison-Wesley, 1979.
Familiar stars in the spectral sequence
STAR COLOR SPECTRAL
CLASS
TEMPERATURE
(K)
COLOR
INDEX
Procyon Blue to white F5 7,000 0.41
Sun White to yellow G2 6,000 0.65
Capella White to yellow G8 5,500 0.79
5,500–7,000 K
Gordon, Gary. Light and Color. May, 1987.
COLOR RENDERING INDEX (CRI)
Lamp color name Apparent color
temperature (Kelvin)
Color Rendering
Index (R)
Warm white 3000 52
Deluxe warm white 2900 73
White 3500 60
Cool white 4200 66
Deluxe cool white 4200 89
Sign white 5200 86
Daylight 7000 79
3,000–7,000 K

From the previous study of electromagnetic radiation in Physics, we learned that color is related to the frequency (or wavelength) of light. Yet color is also related to temperature. For instance, by observing colors of the stars, we could tell which stars are hotter and which ones are cooler.

Since all objects are made up of atoms, which vibrate when thermal energy is received from an outside source. The greater the thermal energy received, the more vigorously the atoms vibrate. If the atoms are vibrating fast enough, it may emit light. Cooler objects emit primarily low frequency waves, while warmer objects emit waves with primarily higher frequencies. Therefore, objects at higher temperatures emit waves of high enough frequency to be visible and we start to see red colored objects, also known as "red hot" objects. If the temperature of an object continues to rise, the emitted wavelengths become even higher in frequency, and the observed color becomes orange or yellow. At even higher temperatures, the amount of visible light emitted by the object covers the entire visible spectrum about equally and our eyes see it as white. This is what is known as a "white hot" object.

According to my research, no matter what kind of materials an object is made of, it will glow white when its temperature is in the range of 1,500 to 11,000 K.

Carine Fang -- 2001