Illustration of a Doomed Asteroid
A new study provides a possible explanation of mysterious X-ray flares detected by Chandra over the period of several years. It suggests that there is a cloud around Sgr A* containing hundreds of trillions of asteroids and comets, stripped from their parent stars. The flares occur when asteroids of six miles or larger in radius are consumed by the black hole. An asteroid that undergoes a close encounter with another object, such as a star or planet, can be thrown into an orbit headed towards Sgr A*, as seen in this series of artist's illustrations. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the Sun, it would be torn into pieces by the tidal forces from the black hole. These fragments would then be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth's atmosphere. A flare is produced and eventually the remains of the asteroid are swallowed by the black hole.
(Credit: Illustrations: NASA/CXC/M.Weiss)

Chandra X-ray Image of Sgr A*
Over several years, astronomers have noticed flares in X-ray light of the black hole at the center of the Milky Way. NASA's Chandra X-ray Observatory detected these flares during observations that the telescope makes of the black hole periodically. A new study suggests that these flares may occur when the black hole -- known as Sagittarrius A* or Sgr A* for short -- consumes an asteroid at least six miles wide. If an asteroid get too close to another object like as a star or planet, it can be thrown into an orbit headed towards Sgr A*. Once the asteroid passes within about 100 million miles of the black hole, it is torn into pieces by the black hole's tidal forces. Eventually, these fragments are vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*. This is what produces an X-ray flare. If confirmed, this result could mean that there is a cloud around Sgr A* containing hundreds of trillions of asteroids and comets. This would be an exciting development for the many scientists who are fascinated by the Milky Way's giant black hole and environment around it.
(Credit: NASA/CXC/MIT/F.K. Baganoff et al./E. Slawik )