What is the coolest color of a star?
Since the temperature of a star can determine its visual color, this category scheme is known as spectral type. The main categories of spectral type are M, K, G, F, A, B, and O. The coolest stars (red dwarfs) being M, and the hottest stars being O. Our own Sun is a G star.
Color also tells us about the temperature of a candle flame. The inner core of the candle flame is light blue, with a temperature of around 1800 K (1500 °C). That is the hottest part of the flame. The color inside the flame becomes yellow, orange, and finally red.
- Note that a blue propane flame is hotter than a yellow one, but this is just due to efficient combustion, and the difference is likely in the hundreds of degrees Kelvin, not thousands. White fire might be something extremely hot, but it's more likely a mixture of several emission spectra.
- Higher the frequency, higher the energy carried, hotter the light. In the visible spectrum of EM radiation — ROYGBIV, violet represents the color maximum frequency. Hence, violet is the color of the hottest light.
- Actually, the hottest part of the candle flame is the blue part, at 1670 degrees F (1400 C.) That is where the flame has the most oxygen and you are getting complete combustion. The reddish part is the coolest part, about 1070 F (800C).
Eta Carinae could be as large as 180 times the radius of the Sun, and its surface temperature is 36,000-40,000 Kelvin. Just for comparison, 40,000 Kelvin is about 72,000 degrees F. So it's the blue hypergiants, like Eta Carinae, which are probably the hottest stars in the Universe.
- Mercury is the planet that is closest to the sun and therefore gets more direct heat, but even it isn't the hottest. Venus is the second planet from the sun and has a temperature that is maintained at 462 degrees Celsius, no matter where you go on the planet. It is the hottest planet in the solar system.
- It's much colder there than anywhere on Earth, despite the fact Venus is closer to the sun. This discovery is a bizarre twist for a planet that is famously hot and inhospitable. Even though Venus is further from the sun, it's hotter than Mercury, the result of a killer greenhouse effect.
- The results are astonishing—the surface temperature of the star at the center of the Red Spider Nebula is an incredible 540,000 degrees F, more than 50 times hotter than the Sun, and 30 times hotter than mighty Sirius.
In general, a star's temperature determines its color, from red to blue-white. Spectral types are named with a letter: M, K, G, F, A, B and O. M stars are the coldest stars and O stars are the hottest. The closest star to the Earth, the sun, is a class G star.
- Astronomers Find Coldest Star in the Universe. Astronomers have detected a new candidate for the coldest known star -- one whose temperature is roughly equivalent to a fresh cup of tea. The object is part of a double system and is a type of star known as a brown dwarf, which is essentially a failed star.
- However, the Sun is essentially all colors mixed together, which appear to our eyes as white. This is easy to see in pictures taken from space. Rainbows are light from the Sun, separated into its colors. Each color in the rainbow (red, orange, yellow, green, blue, violet) has a different wavelength.
- This makes it the largest yellow star known. It is also in the top ten of the largest stars known — 50% larger than the famous red supergiant Betelgeuse — and about one million times brighter than the Sun.
Updated: 21st November 2019