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All spectral colours combined appear white
- The conventional colour description takes into account only the peak of the stellar spectrum. In actuality, however, stars radiate in all parts of the spectrum. Because all spectral colours combined appear white, the actual apparent colours the human eye would observe are far lighter than the conventional colour descriptions would suggest.
en.wikipedia.org/wiki/Stellar_classification
Have you ever given serious consideration to star colours? I often hear people say all stars look white. This is not true. Some show very obvious colour.
- Star colours explained for beginners - BBC Sky at Night Magazine
Why some stars appear white. Inside each eyeball we have...
- Star colours explained for beginners - BBC Sky at Night Magazine
Aug 25, 2023 · Using your naked eye, only the brightest stars are able to activate your cones, which is why fainter ones appear white—that is, colorless.
Why some stars appear white. Inside each eyeball we have cells that enable us to see, called rods and cones. The more numerous rods pick up light intensity, while the cones add in the colour. As the light intensity falls, the cones begin to switch off and go to sleep.
- Types of Stars. The universe’s stars range in brightness, size, color, and behavior. Some types change into others very quickly, while others stay relatively unchanged over trillions of years.
- Main Sequence Stars. A normal star forms from a clump of dust and gas in a stellar nursery. Over hundreds of thousands of years, the clump gains mass, starts to spin, and heats up.
- Red Giants. When a main sequence star less than eight times the Sun’s mass runs out of hydrogen in its core, it starts to collapse because the energy produced by fusion is the only force fighting gravity’s tendency to pull matter together.
- White Dwarfs. After a red giant has shed all its atmosphere, only the core remains. Scientists call this kind of stellar remnant a white dwarf. A white dwarf is usually Earth-size but hundreds of thousands of times more massive.
Most appear white but a few stars such as Antares and Betelgeuse have an orange or reddish hue to them. Others such as Rigel suggest a bluer colour. The colours of stars, however, are not obvious in most stars for several reasons discussed below.
A-type stars are among the more common naked eye stars, and are white or bluish-white. They have strong hydrogen lines, at a maximum by A0, and also lines of ionized metals (Fe II, Mg II, Si II) at a maximum at A5. The presence of Ca II lines is notably strengthening by this point.
People with good color vision acuity can see traces of color in a few of the brightest stars, but most stars appear white. In large telescopes additional stars suddenly take on colors which they lacked to the unaided eye.
