NASA discovers black hole with 'heartbeat'

Houston: Soon after finding the largest black hole last week, NASA has now found another black hole, but it is the tiniest one and with a heart beat. 

A NASA satellite has detected what astronomers said was a "heartbeat" of what could be the smallest known black hole. 

The star-sucker could weigh less than three times the mass of the sun, placing it near the minimum mass required for a black hole to be stable. 

Using the NASA's Rossi X-Ray Timing Explorer (RXTE), which detects X-rays coming from cosmic sources, a team of astronomers identified a specific X-ray pattern, nicknamed a "heartbeat", that indicates that a black hole is present in a binary system with the ordinary star. 

The "heartbeat" pattern is caused by the regular cycles of matter accumulated into the black hole from its neighbouring star. 

"Just as the heart rate of a mouse is faster than an elephant's, the heartbeat signals from these black holes scales according to their masses," said Diego Altamirano, an astrophysicist at the University of Amsterdam, who worked on the NASA project. 

The heartbeat was referring to the intermittent X-ray bursts as gas is sucked from stars, forming a disc around the black hole, where it's heated by friction to millions of degrees, hot enough to emit X-rays. Astronomers have named the new discovery - IGR J1091-3624. 

Astronomers first became aware of the binary system during an outburst in 2003. Archival data from various space missions show it becomes active every few years. 

Its most recent outburst started in February and is ongoing. The system is located in the direction of the constellation Scorpius, but its distance is not well established. It could be as close as 16,000 light-years or more than 65,000 light-years away. 

The potential discovery comes as NASA announced earlier this month the discovery of one of the largest black holes on record. 

Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. 

This discovery from NASA's Chandra X-ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. 

NASA officials say the pair of projects represent the first step and is just the start of a larger program to compare both of these black holes in detail using data from RXTE, NASA's Swift satellite and the European XMM-Newton observatory.