V4641 Sgr
Encyclopedia
V4641 Sagittarii is a variable X-ray binary
star system in the constellation Sagittarius
. It is the source of one of the fastest superluminal jets in our galaxy.
In 1999 a violent outburst at V4641 Sgr revealed it to be the closest known black hole
to Earth. Originally thought to be positioned approximately 1600 ly from Earth, later observations showed it to be at least 15 times further away.
X-ray binary
X-ray binaries are a class of binary stars that are luminous in X-rays.The X-rays are produced by matter falling from one component, called the donor to the other component, called the accretor, which is compact: a white dwarf, neutron star, or black hole.The infalling matter releases...
star system in the constellation Sagittarius
Sagittarius (constellation)
Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...
. It is the source of one of the fastest superluminal jets in our galaxy.
In 1999 a violent outburst at V4641 Sgr revealed it to be the closest known black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
to Earth. Originally thought to be positioned approximately 1600 ly from Earth, later observations showed it to be at least 15 times further away.