In addition, particles of Carbon, like soot, build up in the star's outer layers and diminish their brightness. These stars take a long time to go from maximum to minimum brightness, and are not very predictable. These stars are very diverse, but are named after Mira the Wonderful. There are many different stars classified as eruptive variables. It is unclear why recently formed stars in the Orion Nebula vary in brightness.
Some eruptive stars flare up rapidly.
In some cases of Novas, there are binary star systems in which one star dumps gas from its upper layer onto the other star. This causes the second star to ignite the material and flare up. Eclipsing Binaries Eclipsing Binaries do not physically change in brightness, but instead result from a binary star system angled so that when one star passes in front of the other, it blocks some of its light, and leads to a drop in brightness in the pair. The most prominent eclipsing binary star is Algol in Perseus.