V404 Cygni

V404 Cygni is a binary star system, which is likely to contain a black hole with 12 ± 3 solar masses. The companion star with a spectral type between late G and early K, has a mass that is slightly smaller than the sun. The double star located in the constellation Cygnus. The two stars revolve around each other every 6.5 days and this in a fairly short distance.

The V in the name indicates that it is a variable star. This is always brighter and less over time. The binary star system is also considered as Nova, because there were at least three bright bursts of energy in the 20th century.

However, it is also believed that it is the more massive star instead of a black hole is a quark star.

In 2009, the putative black hole was in the V404 Cygni system, the first in which a precise parallax for its removal could be carried out from our solar system. The distance is 2.39 ± 0.14 kiloparsecs.

Discovery

On May 22, 1989, the Japanese Ginga team had discovered a new X-ray source, which was cataloged as GS 2023 338. This was then identified with the Nova V404 Cygni already known, because its position was consistent.

V404 Cygni

Discovery

Further Reading