A group of scientists led by astrophysicist Smadar Naoz believes that the supermassive black hole Sagittarius A * (Sgr A *), located in the center of the Milky Way, may have a companion.
This potential second black hole has not yet been registered. However, their existence can be corroborated or discarded through "a multitude of observable effects," according to experts.
To Space, astrophysicist Smadar Naoz said the most obvious effect would be the movement of stars closest to the center of the Milky Way, such as S0-2, which orbits Sgr A * over a period of 16 years. If there is a black hole that accompanies it, its size would be no larger than one tenth of the main one, which is a million times larger than the sun.
Observations have made it possible to rule out the existence of “a second supermassive black hole with a mass 100,000 times larger” than that of the sun and is “200 times the distance” between that star and Earth relative to Sgr A *, Naoz explained.
However, these circumstances do not rule out that there is a smaller black hole in this area that “does not alter the orbit of SO-2 in a way that we can easily measure,” the expert added.
Thus, the presence of a second black hole would be detected by observing the emission of S0-2 at its maximum approximation to Sgr A *, a phenomenon that will occur in about 16 years and in which “the expected result could be altered” .
In addition, the interaction of the two black holes should release very low frequency gravitational waves. Devices available today are unable to detect such fluctuations, but the Laser Interferometer Space Antenna (LISA) that NASA expects to be operational in 2034 will be able to record them in the future.
The study is available on the ArXiv prepress server.