High Quality Content by WIKIPEDIA articles! The start of using the astronomical X-number notation for an astronomical X-ray source in a constellation came from the initial discoverers of an extrasolar X-ray source at the American Science and Engineering Company-Massachusetts Institute of Technology. The constellation genitive followed by X and a digit became a designation for the X-ray source. Researchers at the US Naval Research Laboratory suggested "XR" rather than "X". Among the first 17 catalogued astronomical X-ray sources are Scorpius X-1 to X-3, X-1 and X-2 Sagittarius, and X-1 to X-4 Cygni. Later, the sources became simply the constellationfollowed by X-#.

Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.