M33 X-7
Encyclopedia
M33 X-7 is a black hole binary system in the galaxy M33
. The system is made up of a stellar mass black hole and a companion star. M33 X-7 is the largest known stellar black hole with an estimated mass of 15.7 times that of the Sun. The total mass of the system is estimated to be around 85.7 times that of the sun which would make it the most massive black hole binary system.
which is approximately 3 million light years (ly) distance from the Milky Way
in constellation Triangulum. This would make M33 X-7 one of the furthest confirmed stellar mass black holes known.
and the Gemini telescope on Mauna Kea, Hawaii.
The properties of the M33 X-7 binary system are difficult to explain using conventional models for the evolution of massive stars. The parent star for the black hole must have had a mass greater than the existing companion to have formed a black hole before the companion star. Such a massive star would have had a radius larger than the present separation between the stars, so the stars must have been brought closer while sharing a common outer atmosphere. This process typically results in a large amount of mass being lost from the system, so much that the parent star should not have been able to form a 15.7 solar-mass black hole
In new models of the formation of the black hole, the star that will form the black hole is nearly 100 times the mass of our sun, orbiting a second star with mass of about 30 solar masses.
In such an orbit, the future black hole is able to start transferring mass while it is still fusing hydrogen into helium. As a result, it loses most of its hydrogen becoming a Wolf-Rayet star and shedding the rest of the envelope in the form of stellar wind, exposing its core. Its companion grows more massive in the process, becoming more massive of the two stars.
Finally, the star collapses creating the black hole, and begins absorbing material from its companion, leading to X-ray emissions.
M33
M33, M-33, or M.33 may refer to:* M-33 , a state highway in Michigan* M33 cluster bomb, a Cold War-era U.S. biological cluster bomb* HMS M33, an M29-class monitor warship of the Royal Navy...
. The system is made up of a stellar mass black hole and a companion star. M33 X-7 is the largest known stellar black hole with an estimated mass of 15.7 times that of the Sun. The total mass of the system is estimated to be around 85.7 times that of the sun which would make it the most massive black hole binary system.
Location
M33 X-7 lies within the Triangulum GalaxyTriangulum Galaxy
The Triangulum Galaxy is a spiral galaxy approximately 3 million light years from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598, and is sometimes informally referred to as the Pinwheel Galaxy, a nickname it shares with Messier 101...
which is approximately 3 million light years (ly) distance from the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
in constellation Triangulum. This would make M33 X-7 one of the furthest confirmed stellar mass black holes known.
System
M33 X-7 orbits a companion star that eclipses the black hole every 3.45 days. The companion star also has an unusually large mass, 70 times that of the Sun. This makes it the most massive companion star in a binary system containing a black hole.Observational data
The black hole was studied in combination by NASA's Chandra X-ray ObservatoryChandra X-ray Observatory
The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. It was named in honor of Indian-American physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit.Chandra...
and the Gemini telescope on Mauna Kea, Hawaii.
The properties of the M33 X-7 binary system are difficult to explain using conventional models for the evolution of massive stars. The parent star for the black hole must have had a mass greater than the existing companion to have formed a black hole before the companion star. Such a massive star would have had a radius larger than the present separation between the stars, so the stars must have been brought closer while sharing a common outer atmosphere. This process typically results in a large amount of mass being lost from the system, so much that the parent star should not have been able to form a 15.7 solar-mass black hole
In new models of the formation of the black hole, the star that will form the black hole is nearly 100 times the mass of our sun, orbiting a second star with mass of about 30 solar masses.
In such an orbit, the future black hole is able to start transferring mass while it is still fusing hydrogen into helium. As a result, it loses most of its hydrogen becoming a Wolf-Rayet star and shedding the rest of the envelope in the form of stellar wind, exposing its core. Its companion grows more massive in the process, becoming more massive of the two stars.
Finally, the star collapses creating the black hole, and begins absorbing material from its companion, leading to X-ray emissions.