2006-09-12 01:08:11 · 7 answers · asked by NURUL FATIN M 1 in Science & Mathematics ➔ Physics
By checking the intensity of the light from the stars, the wavelengths of the light, and comparing it with the wavelengths of the radiated heat from another object which is hot but can have its temperature measured, then they can compare and predict the temperature of the stars.
Simplified, compare the changes in physical properties that can be observed for a hot object and a star, such as the colour, then deduce the relationship between the colour and the temperature using the hot object as your "reference point" and the star as the object which you measure.
One method of doing so is called X-ray spectroscopy.
2006-09-12 01:15:14 · answer #1 · answered by lkraie 5 · 0⤊ 0⤋
By observing its output intensity at different wavelengths.
THe output of all thermally radiating bodies obeys a 'black body' curve. The wavelength of the peak intensity of the curve depends on the body's temperature. The hotter the temperature, the shorter the wavelength.
The hottest stars appear blue, cool ones red. Interstellar dust is at a much lower temperature, and so emits in the IR and milimetre wavelength bands. Hot gas around galaxy cluster and black holes is so hot that it has its peak in X-rays.
Our sun has a surface temp. of about 6000K and appears yellow.
As an interesting aside - our atmosphere is opaque to all electromagnetic radiation bands except radio and visible light. Our eyes are most sensitive to yellow light, the peak output of the sun.
2006-09-12 09:08:23 · answer #2 · answered by Morgy 4 · 0⤊ 0⤋
They use Wein's law
They measure all the wavelengths radiating from the stars. They draw a graph and find out the most common wavelength
The they calculate by using Wein's formula acc to which
temperature=wein's constant/wavelength
2006-09-12 09:27:18 · answer #3 · answered by amandeep s 3 · 0⤊ 0⤋
A hot object radiates heat, and the frequency (color) it gives off varies with the temperature.
We see it here on earth, metal can be heated red hot, or white hot.
Anyway, with clever measurements one can deterimine the temperature.
2006-09-12 08:14:39 · answer #4 · answered by Computer Guy 7 · 0⤊ 0⤋
i am not sure, but i think they have these devices that measure several factors affecting the temperatures of the stars.. maybe like radiation or someting...
2006-09-12 08:13:37 · answer #5 · answered by pat 2 · 0⤊ 0⤋
Using a spectphotometer, and measuring the red shift
2006-09-12 08:14:55 · answer #6 · answered by Master Mind 1 · 0⤊ 1⤋
They might be taking into account a number of factors. Colour alone may sometimes give erroneous results.
2006-09-12 08:44:40 · answer #7 · answered by orsel 2 · 0⤊ 0⤋