Science Daily - October 18, 2007
Astronomers have located an exceptionally massive black hole in orbit around a huge companion star. This result has intriguing implications for the evolution and ultimate fate of massive stars.
The black hole is part of a binary system in M33, a nearby galaxy about 3 million light years from Earth. By combining data from NASA's Chandra X-ray Observatory and the Gemini telescope on Mauna Kea, Hawaii, the mass of the black hole, known as M33 X-7, was determined to be 15.7 times that of the Sun. This makes M33 X-7 the most massive stellar black hole known. A stellar black hole is formed from the collapse of the core of a massive star at the end of its life.
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Thursday, October 18, 2007
Wednesday, October 17, 2007
Most Massive Stellar Black Hole Found in Binary System
National Geographic - October 17, 2007
A strange black hole locked in a tight orbit with a huge star in a nearby galaxy could be the most massive stellar black hole known, astronomers say.
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Astronomers soon realized that the companion star passes directly in front of the black hole on its three-day orbit, eclipsing the black hole's x-ray emissions.
This arrangement allowed the team to combine data from NASAs orbiting Chandra X-Ray Observatory and the Gemini North Telescope on Mauna Kea, Hawaii, to calculate the two object's masses more accurately than usual.
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A strange black hole locked in a tight orbit with a huge star in a nearby galaxy could be the most massive stellar black hole known, astronomers say.
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Astronomers soon realized that the companion star passes directly in front of the black hole on its three-day orbit, eclipsing the black hole's x-ray emissions.
This arrangement allowed the team to combine data from NASAs orbiting Chandra X-Ray Observatory and the Gemini North Telescope on Mauna Kea, Hawaii, to calculate the two object's masses more accurately than usual.
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Heavyweight black hole is a record breaker
New Scientist - October 17, 2007
A black hole as heavy as almost 16 Suns has set a new weight record for black holes that form from collapsing stars. Its discovery suggests that there may be even heavier ones lurking out there, spawned in the death throes of the universe's most massive stars.
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The companion star is itself a brute, some 70 times the Sun's mass. Jerome Orosz of San Diego State University in California and colleagues used the 8.2-metre Gemini North telescope at Mauna Kea, Hawaii, to work out the orbit precisely and pin down the black hole's mass (Nature, DOI: 10.1038/nature06218).
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A black hole as heavy as almost 16 Suns has set a new weight record for black holes that form from collapsing stars. Its discovery suggests that there may be even heavier ones lurking out there, spawned in the death throes of the universe's most massive stars.
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The companion star is itself a brute, some 70 times the Sun's mass. Jerome Orosz of San Diego State University in California and colleagues used the 8.2-metre Gemini North telescope at Mauna Kea, Hawaii, to work out the orbit precisely and pin down the black hole's mass (Nature, DOI: 10.1038/nature06218).
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Heaviest stellar black hole discovered in nearby galaxy
PhysOrg.com - October 17, 2007
The main component of this graphic is an artist's representation of M33 X-7, a binary system in the nearby galaxy M33. In this system, a star about 70 times more massive than the Sun (large blue object) is revolving around a black hole. This black hole is almost 16 times the sun's mass, a record for black holes created from the collapse of a giant star. Other black holes at the centers of galaxies are much more massive, but this object is the record-setter for a so-called "stellar mass" black hole. ... Observations by the Gemini telescope on Mauna Kea, Hawaii track the orbital motion of the companion around the black hole, giving information about the mass of the two members of the binary. ...
Wednesday, October 10, 2007
Baby Booms And Birth Control In Space
Science Daily — September 25, 2007
Stars in galaxies are a bit similar to people: during the first phase of their existence they grow rapidly, after which a stellar birth control occurs in most galaxies.
New observations from Dutch astronomer Mariska Kriek with the Gemini Telescope on Hawaii and the Very Large Telescope (VLT) in Chile, have shown that a part of the heavy galaxies already stopped forming stars when the universe was still a toddler, about 3 billion years old. Astronomers suspect that black holes exert an influence on this halt in births.
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Stars in galaxies are a bit similar to people: during the first phase of their existence they grow rapidly, after which a stellar birth control occurs in most galaxies.
New observations from Dutch astronomer Mariska Kriek with the Gemini Telescope on Hawaii and the Very Large Telescope (VLT) in Chile, have shown that a part of the heavy galaxies already stopped forming stars when the universe was still a toddler, about 3 billion years old. Astronomers suspect that black holes exert an influence on this halt in births.
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