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The Question
(Submitted November 30, 1996)
What is known about Sagittarius A*,the center of our galaxy ?
The Answer
Sgr A* at the center of Milky Way is probably a massive black hole of
about a million solar masses (the mass of the Sun). The mass is estimated
from the motion of gas and stars in the region. Although Sgr A* is gathering
mass from its vicinity at a rate of about 10E-4 solar masses per year, a
rather high rate, it is not as bright as would be expected. Therefore,
Sgr A* is extremely inefficient (one part in 100,000) in converting the
gravitational energy of the gathered material into radiation.
Koji Mukai
with helps from Drs. Chen, Loewenstein and Snowden
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