Tuesday, February 14, 2012

Milky Way’s black hole ‘eating’ asteroids

Washington: The supermassive black hole at the heart of the Milky Way may be devouring asteroids on a daily basis, a new study based on findings by Nasa’s Chandra spacecraft has suggested. The Chandra X-ray Observatory, named in honour of Indian physicist Subrahmanyan Chandrasekhar, has been detecting Xray flares about once a day coming from our galaxy’s central black hole known as Sagittarius A* (Sgr A*)for several years.

Now, researchers found that these flares may actually be caused by asteroids falling into the black hole’s maw.

“People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole,” said lead study author Kastytis Zubovas of University of Leicester in the UK.

“It’s exciting because our study suggests that a huge number of them are needed to produce these flares,” Zubovas said. The researchers suggested
that a cloud around Sgr A* con
tains trillions of asteroids and comets that the black hole stripped from their parent stars.

Asteroids passing within 160 million km of the black hole — roughly the distance between the Earth and the Sun — are likely torn to pieces by Sgr A*’s gravity, they said. These fragments would be vaporized by friction as they encounter the hot gas flowing onto the black hole, much as meteors are burned up by gases in Earth’s atmosphere. This vaporization, they said, likely spawns the X-ray flares, which last for a few hours and range in brightness from a few times to nearly 100 times that of black hole’s regular output.

Sgr A* then swallows up what’s left of the close-flying asteroid, added the researchers who detailed their findings in the ‘Monthly Notices of the Royal Astronomical Society’. PTI


STELLAR DELIGHT: A Nasa illustration shows a supermassive black hole at the centre of our Milky Way Galaxy consuming asteroids