Cygnus X-3


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Cygnus X-3

A luminous X-ray binary source with an unusually short (4.8 hour) binary period. The short period suggests that the system consists of a neutron star and a low-mass companion. Recent infrared spectra show strong helium emission lines as for a Wolf-Rayet companion star. The sinusoidal X-ray light curve is interpreted as being due to scattering of X-rays from the (unseen) central source by a hot dense wind driven off the companion star. Cygnus X-3 occasionally produces strong sometimes violent radio flares, first observed in 1972, between which it shows variable radio emission with a dominant component having a periodicity of 4.8 hours, similar to the X-ray period. Extremely high energy (>1015 eV) gamma rays have also been detected, though not recently. These observations make Cygnus X-3 a unique source. It is postulated that the unusual properties may arise from very rapid rotation of the neutron star embedded in the dense wind of its companion star.

Cygnus X-3

[′sig·nəs ‚eks ′thrē]
(astrophysics)
A variable source of x-rays, with a period of 4.8 hours, associated with a variable radio source that flared up to enormous levels in September 1972 with no observed increase in x-ray emission. Abbreviated Cyg X-3.
References in periodicals archive ?
Details about the Cygnus X-3 gamma rays may also shed light on how distant quasars pump even greater amounts of energy into space.
The microquasar is a binary system known as Cygnus X-3.
The Cygnus Mystery proposes that the cause of this sudden shift lay in a sudden spike in the cosmic rays reaching Earth, offering evidence that the rays, which have left behind subatomic traces in deep caves, emanated from the binary star system Cygnus X-3. A handful of color photographic plates illustrate this blend of archaeo-astronomy, scientific revolution and spiritual wisdom.
These include the field of the energetic black hole Cygnus X-1, clearly detected as a point source in each telescope, together with Cygnus X-3. The SPI instrument is also detecting gamma-ray bursts at a rate of one per day.
In October, Chandra examined Cygnus X-3, a neutron star orbiting a companion star every 4.8 hours.
Astronomers call Cygnus X-3 one of the most bizarre objects in the heavens.
Indications that gamma rays also emerge from Cygnus X-3, an X-ray-emitting binary star system, appear less compelling.
In 1983, Manfred Samorski and Wilhelm Stamm of West Germany's University of Kiel reported similar signals coming from the pulsar Cygnus X-3. Now, researchers are taking a closer look at a number of star systems known to be sources of peculiar emissions.
A particularly likely class of candidates is the binary star X-ray sources in our galaxy, such as Cygnus X-3, Hercules X-1 and Vela X-1.
However, it makes a real appearance in the mechanism he suggests to explain the strange radiation coming from the X-ray pulsar Cygnus X-3. A detector deep in a mine in northern Minnesota has shown evidence for highly energetic particles coming straight to us from Cyg X-3 (SN: 4/11/87, p228).
Presumably these muons are produced in the detector by some highly energetic, extremely penetrating radiation that comes from certain sources in the sky-- Cygnus X-3 and Hercules X-1 are among those implicated--and can penetrate the earth's atmosphere and several thousand feet of rock to reach the detector.
The controversy is complicated by questions of timing andthe possible variability of the presumed source of cygnets, the X-ray source Cygnus X-3. Cygnus X-3 seems to undergo a strong outburst every autumn, and observers had awaited the 1986 outburst as an opportunity to settle the question.