シリウス

At apparent magnitude −1.44, Sirius is the brightest star in Earth's night sky, outshining every stellar rival by a clear margin. Catalogued as Alpha Canis Majoris, it anchors the constellation Canis Major and lies only 8.6 light-years away — one of the Sun's nearest neighbours. Its white colour, mirrored in a near-neutral B–V index of 0.009, marks it as an A-type star. Much of the star's prominence stems from that closeness rather than raw power: an absolute magnitude of 1.45 is only moderately luminous, so Sirius blazes chiefly because it is near. From a declination of −16° it rides the southern half of the celestial sphere yet stays visible across most inhabited latitudes.