Cygnus X-1とは 意味・読み方・使い方

Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 2.3×10⁻²³ Wm⁻²Hz⁻¹ (2.3×10³ Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole candidate and it remains among the most studied astronomical objects in its class. It is now estimated to have a mass about 8.7 times the mass of the Sun and has been shown to be too compact to be any known kind of normal star or other likely object besides a black hole. If so, the radius of its event horizon is probably about 26 km.