Another remarkable fact lately discovered is that the different types of stars are not indiscriminately scattered through space. Our own sun seems to be surrounded, to a distance of about 100 light-years, by suns more or less like himself, while the greater number of the red Antarian stars lie at a much greater distance from us. Most distant of all, considered as a class, are the bluest of the Orion stars; for though the distances of individuals vary greatly, the average distance of these stars from us is more than 500 light-years. Yet they are often very bright, so this is another proof of their great intrinsic brilliancy.
VI
DOUBLE AND MULTIPLE STARS
Among the brighter stars at least one in four is double, and I shall only mention a few which for different reasons are of special interest.
The brightest double in the sky has already been mentioned, α Centauri, and we have also described another southern pair scarcely less brilliant, α Crucis, Sirius with his very dim companion, Rigel and Antares with theirs of contrasting colours. Other fine southern doubles are:
β Piscis australis, a white star with reddish companion, visible in a 3-inch telescope.
δ Corvi, an unequal distant pair, pale yellow and bluish, easily separated in a 4½-inch telescope.
σ Scorpii (near Antares), white and blue.
32 Eridani, yellow and blue-green—“magnifici, superbi,” according to Secchi.
β Capricorni (close to the splendid naked-eye double α Capricorni), orange-yellow and blue.
γ Crucis, orange-yellow, companion fifth magnitude, rather distant.