How can a red star be brighter than blue star?

Can you think of a way in which a red star could be more luminous (actually give off more light) than a blue star?|||By being A LOT bigger.



In this particular question, being close to the solar system DOES NOT count as making it more luminous. It only counts as making it APPEAR more bright, but it does not count as making it actually BE more luminous.



That red star would need to be a red giant or a red supergiant. For instance, red Betelgeuse is a lot bigger than blue Bellatrix, and Betelgeuse is about ten times as luminous as Bellatrix.





The red main sequence stars are red dwarfs. They are never brighter than the blue main sequence star types.



http://www.daviddarling.info/images/Hert鈥?/a>|||Size matters here. So does proximity.



Sirius is less than 9 lightyears away and is the brightest in the northern hemisphere -- magnitude

-1.45.



Betelgeuse is a magnitude 0.45 and is 427 lightyears away.



Antares is a magnitude 1.05 and is 600 lightyears away.



If Antares and Betelgeuse were only 9 lightyears away they would both far outshine Sirius. Deneb is even more impressive.|||If you are talking about the intensity, then blue star is more intense than red star. Please be more specific as if what you mean by brightness?|||There are three ways a star can be bright: large, hot, or close. By specifying colors in your question, you have eliminated the hot option, as blue stars are much hotter than the red. Thus a red star can be brighter by being larger (red giant) or closer.|||If it is a lot bigger, it would have more surface area. Then it could be more lumious. See Betelgeuse or Antares.


If it was a lot closer to us, it could appear brighter.