I have a question about the color of a black-body radiator that has been baffling me for a few years now, and I haven't been able to find a satisfactory answer. So, we know that a star's color depends on its temperature, as determined by Planck's law. For example, a cool M-type dwarf (temperature of 2-4 KK) will appear red. A G or F-type star with a temp of 5-7 KK will appear yellow or white. An O-type star with a temp of 30 KK will appear blue. However, it looks like the same relationship doesn't hold true for a hot object, say a metal. We know a heated object starts glowing red when the temperature is beyond the Draper point at 525°C. It then turns to bright orange at around 900°C, then bright yellow at 1200°C, and finally white at temps above 1400°C. So, as we can see, there is a huge difference between the color-temperature relation of stars and everyday objects, even though their thermal radiation is governed by the same physical laws. Why is that?
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