| Abstract from DBPedia | A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either:
* Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.
* Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle.変光星（へんこうせい、Variable star）は、天体の一種で、明るさ（等級）が変化するもののことである。大まかに爆発型変光星、脈動変光星、回転変光星、激変星、食変光星（食連星）、X線変光星の6種類に分類される。 (Source: http://dbpedia.org/resource/Variable_star) |
