Ome-2

Its story

Omega-2 Aquarii is a blue-white main-sequence star in the Water Bearer. In 1953, Johnson and Morgan chose it as the photometric standard defining class B9.5V: in astronomy, its light has become a ruler. At 149 light-years, it spins on itself every ten and a half hours at 148 km per second, and ranks among the hundred strongest stellar X-ray sources within fifty parsecs of the Sun. An A-type companion shares the system at 5.7 arcseconds.