The smallest black hole has ever been recorded

Using a new method, two NASA scientists have identified the lightest black hole ever known. With a mass of about 3.8 times heavier than the Sun and only about 15 miles in diameter, this black hole is so close to the smallest size that it is predicted that black holes are born from dead stars.

According to lead author Nikolai Shaposhnikov, of NASA's Goddard Aerospace Center in Greenbelt, 'This black hole is actually approaching the limit. For years astronomers have wanted to know what the smallest possible size of a black hole is, and this black hole is a big step forward for us to answer that question. '

Shaposhnikov and his Goddard Lev Titarchuk colleagues introduced their results on March 31 at the meeting of the High-Energy Astrophysics Department, the American Astronomical Council, in Los Angeles, California. Titarchuk also works at George Mason University in Fairfax, and the US Naval Laboratory in Washington.

This tiny black hole is located in the Double Galaxy Milky Way called XTE J1650-500, named after the coordinates in the south of the constellation Ara. NASA's Rossi Timing Explorer (RXTE) X-ray satellite discovered the system in 2001. Once J1650 was discovered astronomers noticed that it contained a normal star and a light black hole. But the volume of black holes has never been measured to a high degree of accuracy.

The smallest mass black hole ever known belongs to a binary system called XTE J1650-500.This black hole has 3.8 times the mass of the Sun and has a companion star around it as shown in this illustration.(Photo: NASA / CXC / A. Hobar)

The method used by Shaposhnikow and Titarchuk has been described in several papers in the Astrophysical Journal. This method uses the relationship between black holes and the inner part of the plates around them, where the gas travels in a spiral before crashing into it. When this process reaches moderate speed, hot air accumulates near the black hole and emits a stream of X-rays. The intensity of X-rays changes in a repeating pattern according to intervals. This signal is called a quasi-periodic oscillation (QPO).

Astronomers have long suspected that the frequency of a QPO depends on the mass of the black hole. In 1998, Titarchuk found that the congestion floor was close to small black holes, so the QPO rhythm was quite fast. When the black hole increases mass, the congestion layer is pushed away so the QPO rhythm slows down. To measure the mass of black holes, Shaposhnikov and Titarchuk use data from RXTE. This satellite has accurately measured the QPO frequencies of at least 15 black holes.

Last year, Shaposhnikov and Titarchuk applied the QPO method to three black holes whose mass was measured by other methods. In their new paper, they extended the results to seven other black holes, three of which were mass-determined. 'In each case, our measurements correspond to other methods. We know that this method will succeed because it has passed the test with excellent results. '

When Shaposhnikov and Titarchuk applied this measure to XTE J1650-500, they calculated a mass of 3.8 times the mass of the Sun , a margin of difference of only about half the Sun. This figure is much lower than the previous black hole record, GRO 1655-40 - reliable measures for a mass of 6.3 solar masses.

Under an important threshold that is unknown, a dying star will produce a neutron star instead of a black hole. Astronomers believe that the boundary between black holes and neutron stars is between 1.7 and 2.7 solar masses. Understanding this sacred line is very important for basic physics, because it will give scientists the behavior of matter when it is crushed into conditions of unusually high density.

Although this record black hole has a small volume, astronauts should be vigilant. Smaller black holes similar to this black hole in J1650 release tidal waves more powerful than the larger black holes found in galactic centers, making it difficult to access small black holes.'If you want to venture closer to J1650's black hole, its gravity will stretch you as long as an Italian pasta.'

Shaposhnikov adds that RXTE is the only tool that can perform timely observations with high accuracy, the kind of observation that is essential for this research flow.'RXTE is absolutely important for black hole volume calculations.'