Cygnus X-1


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Cygnus X-1

An intense galactic X-ray source and the first to yield good observational evidence for the existence of a black hole of stellar mass. Identification of Cygnus X-1 in 1971 with the luminous supergiant star HDE 226868 was followed by the discovery of a 5.6-day binary period. Analysis of the optical observations showed the mass of the ‘unseen’ companion star (the X-ray source) to lie in the range 6–15 solar masses, well above the limit allowed for a neutron star (≤ 3 solar masses) or white dwarf (≤ 1.4 solar masses). Support for the view that Cygnus X-1 involves gas accretion from the optical supergiant onto a black hole is provided by the rapid (millisecond) and irregular variability of the X-ray emission.

Cygnus X-1

[′sig·nəs ‚eks ′wən]
(astrophysics)
A source of x-rays whose intensity varies in an irregular manner, associated with a weak variable radio source and a ninth-magnitude spectroscopic binary star, designated HDE226868, that consists of a blue supergiant and an invisible companion, which may be a black hole. Abbreviated Cyg X-1.
References in periodicals archive ?
Sep 23-Oct 23 LIBRA CYGNUS X-1 is rising in your sign this week, as Venus is in the declension.
Gamma Rays "Energetic radiation from Cygnus X-1 has given astronomers new hints about the nature of this enigmatic object, which lies in the Milky Way some 8,000 light-years from us.
Hawking also broke into the office of another CalTech physicist, Kip Thorne, in order to covertly concede that the mysterious celestial object Cygnus X-1 was a black hole.
Studies of radio emissions from Cygnus X-1 support claims that it is a black hole (9/23/72, p.
Using several telescopes, both ground-based and in orbit, the scientists unraveled longstanding mysteries about the object called Cygnus X-1, a famous binary-star system discovered to be strongly emitting X-rays nearly a half-century ago.
Over three decades ago, Stephen Hawking placed - and eventually lost - a bet against the existence of a black hole in Cygnus X-1.
A fines de la decada de los 60 se descubrio la estrella Cygnus X-1, una estrella super-gigante azul caliente, que por su comportamiento parece que sufre los efectos de un agujero negro.
In 1971 an X-ray-detecting satellite found irregular changes in an X-ray source in the constellation of Cygnus, a source that had been named Cygnus X-1.
Jul 23-Aug 23 LEO CYGNUS X-1 is rising in your sign this week as Venus is in the declension.
Backyard telescope users seeking to spot a stellar-mass black hole, or the next closest thing, have one good option: Cygnus X-1, which is locked in a close, 5.
Using several telescopes, both ground-based and in orbit, the scientists unravelled longstanding mysteries about the object called Cygnus X-1, a famous binary-star system discovered to be strongly emitting X-rays nearly a half-century ago.
Analyzing a trove of data collected nearly a decade ago by the Hubble Space Telescope, astronomers observed what seems to be the last gasp emitted by gaseous material spiraling into Cygnus X-1, a suspected black hole 6,000 light-years from Earth.