A blue point of light in the constellation Telescopium gleams overhead during winter in the Southern Hemisphere. The brilliant pinprick on the sky, which looks like a bright star, is actually two closely orbited stars — accompanied by the nearest known black hole on Earth.
The recently found black hole in star system HR 6819 is about 1,011 light-years from our solar system. The unseen body, revealed today in Astronomy & Astrophysics, is locked in an orbit with two visible stars. It is estimated to be about four times the sun 's mass, and about 2,500 light-years closer to the nearest black hole.
"It's in our backyard on the scale of the Milky Way," Thomas Rivinius, an astronomer at the European Southern Observatory (ESO) in Chile who led the latest study, told "Almost at our doorstep."
Consider some of the best-known black holes in astronomy for instance, the ones usually interesting enough to make headlines. The black hole at the center of our Milky Way galaxy is more than 25,000 light-years away, and the black hole found by astronomers in unprecedented detail last year lies 55 million light-years away, in an entirely different galaxy. This one, on the other hand, is so close that the pair of stars which orbit the black hole can be seen with the naked eye on a clear night in the Southern Hemisphere, far from light pollution. The stars show up from here as a single pinprick of light.
Rust, invisible holes. The way to locate the darkest points of the World is to look around for luminous clues. Most of the black holes found by astronomers in our galaxy — a few dozen — were spotted because they devoured nearby stars, pulled material into their maws, and gone past a point of no return. The mechanism is so luminous that it is not only possible to spot black holes from Earth, but also they are also difficult to stop. "Sometimes they are the brightest objects in the sky," in reality some black holes emit so much radiation as they eat that without frying their electronics, telescopes can not look at them.
The newly identified black hole does not fall into that category. This exists inside a two-star system but it's not close enough to ruin their day either. Astronomers did not go in search of the black hole either; they began to explore this system , known as HR 6819, as part of a pair-orbiting star analysis years ago. When analyzing the data they found something odd about HR 6819, particularly the inner star's behaviour. The velocity of the star was so extreme that astronomers suspected there was a third object lurking nearby and flinging around it.
Curiously, black holes aren't really black. Quasars-objects formed by black holes in the cores of distant galaxies-are supremely white. Combined they will comfortably outshine the rest of their host galaxy. Such radiation is produced when new material feasts on the black hole. To be clear: this material is still outside the horizon of the event and that is why we can still see it. Below the surface of events is where nothing will escape, not even water. It will shine as the whole matter piles up from the feast. As observers look at quasars, it is this light which is seen.
But this is an problem for anything that orbits (or is close to) a black hole, as it is also very hot.
The recently found black hole in star system HR 6819 is about 1,011 light-years from our solar system. The unseen body, revealed today in Astronomy & Astrophysics, is locked in an orbit with two visible stars. It is estimated to be about four times the sun 's mass, and about 2,500 light-years closer to the nearest black hole.
"It's in our backyard on the scale of the Milky Way," Thomas Rivinius, an astronomer at the European Southern Observatory (ESO) in Chile who led the latest study, told "Almost at our doorstep."
Consider some of the best-known black holes in astronomy for instance, the ones usually interesting enough to make headlines. The black hole at the center of our Milky Way galaxy is more than 25,000 light-years away, and the black hole found by astronomers in unprecedented detail last year lies 55 million light-years away, in an entirely different galaxy. This one, on the other hand, is so close that the pair of stars which orbit the black hole can be seen with the naked eye on a clear night in the Southern Hemisphere, far from light pollution. The stars show up from here as a single pinprick of light.
The newly identified black hole does not fall into that category. This exists inside a two-star system but it's not close enough to ruin their day either. Astronomers did not go in search of the black hole either; they began to explore this system , known as HR 6819, as part of a pair-orbiting star analysis years ago. When analyzing the data they found something odd about HR 6819, particularly the inner star's behaviour. The velocity of the star was so extreme that astronomers suspected there was a third object lurking nearby and flinging around it.
Curiously, black holes aren't really black. Quasars-objects formed by black holes in the cores of distant galaxies-are supremely white. Combined they will comfortably outshine the rest of their host galaxy. Such radiation is produced when new material feasts on the black hole. To be clear: this material is still outside the horizon of the event and that is why we can still see it. Below the surface of events is where nothing will escape, not even water. It will shine as the whole matter piles up from the feast. As observers look at quasars, it is this light which is seen.
But this is an problem for anything that orbits (or is close to) a black hole, as it is also very hot.