Astronomers have detected the fastest known star in the Milky Way, hurtling around the supermassive black hole at the heart of the galaxy.<\/p>\n
The star, called S301, travels at about 25,000km (15,500 miles) per second, 100,000 times faster than a commercial plane. It is also the closest known star to the Milky Way\u2019s central black hole, Sagittarius A*, approaching it around the distance of Saturn to the Sun.<\/p>\n
\u201cWhat is special about this star is that it\u2019s orbiting Sagittarius A* on a very tight orbit, taking just 8.7 years to complete it, and is approaching the black hole at a mere 12 times the distance of Earth to the sun. That is unprecedented,\u201d said Felix Mang, a PhD student at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, and an author of the study published on the findings.<\/p>\n
The star\u2019s extreme proximity to Sagittarius A* means that it could open a new window on to the black hole\u2019s fundamental properties and the extreme environment surrounding it.<\/p>\n
Like many objects in the night sky, black holes are predicted to spin. According to Einstein\u2019s general theory of relativity, a spinning black hole drags spacetime along with it, warping the orbits of surrounding stars. This effect is only meaningful for objects orbiting fast-rotating black holes at close range.<\/p>\n
S301 appears to have the perfect combination of a highly eccentric (lopsided) and very tight orbit.<\/p>\n
\u201cFor the first time, we would actually be able to measure very directly the spin of a massive black hole, which would be a key test of Einstein\u2019s theory,\u201d said Dr Stefan Gillessen, a senior scientist at MPE and a co-author of the study, which is published in the journal Nature<\/a>.<\/p>\n A sequence of images from the ESO\u2019s VLTI shows several stars orbiting Sagittarius A*. S301 passes closer to Sagittarius A* than the others; the solid curve shows the portion of its orbit already completed, while the dashed curve shows the path it will follow. Photograph: ESO\/Gravity\/Reuters<\/p>\n Previously it had been assumed it would require measuring the motion of multiple stars for several decades to estimate the spin of Sagittarius A*. The scientists were able to trace S301\u2019s orbit back to 2017 and, by tracking it through its next closest passage in 2031, hope to have enough data.<\/p>\n \u201cWith this star we hope to measure, within the next 10 years, the spin of the black hole,\u201d said Mang.<\/p>\n