Astronomers have discovered a black hole with a mass more than 33 times that of our Sun, the largest known in the Milky Way apart from the supermassive black hole lurking at the center of our galaxy.
The newly identified black hole is located about 2,000 light-years from Earth—relatively close in cosmological terms—in the constellation Aquila, and has a companion star orbiting it. A year, 5.9 trillion miles.
Black holes are extraordinarily dense objects with gravity so strong that not even light can escape, making them difficult to detect. This one was identified by observations made on the European Space Agency’s GAIA mission, which creates a massive population, because it caused a wobble motion in its companion star. Data from the Chilean-based Extremely Large Telescope of Southern Europe and other ground-based observatories were used to verify the black hole’s mass.
“This black hole is not only very massive, but also very strange in many aspects. It is something we do not expect to see,” said Pasquale Panozzo, a research engineer at the French research agency CNRs at the Paris Observatory and author of the study published in the journal Astronomy and Astrophysics. never “.
For example, the black hole, called Gaia BH3, and its companion are traveling within the galaxy in the opposite direction to how stars normally orbit in the Milky Way.
The researchers said that Gaia BH3 was formed after the death of a star that was more than 40 times as massive as the Sun.
Black holes that result from the collapse of a single star are called stellar black holes. GAIA BH3 is a known supermassive black hole, according to astronomer and co-author Tsevi Mazeh of Tel Aviv University in Israel.
Stellar black holes are dwarfed in size by the supermassive black holes that live at the center of most galaxies. One such black hole, called Sagittarius A*, or Sgr A*, is located at the heart of the Milky Way. It has 4 million times the mass of our Sun and is located about 26,000 light-years from Earth.
The progenitor star Gaia BH3 consisted almost entirely of hydrogen and helium. Stars in the early universe had such a chemical composition, known as low metallicity. This star formed relatively early in the history of the universe – perhaps two billion years after the Big Bang event.
When that star exploded at the end of its life—dubbed a supernova—some of the material was blown out into space while its remains violently collapsed to form a black hole.
The discovery of GAIA BH3, according to Mr. Panozzo, supports models of stellar evolution showing that massive stellar black holes could only be produced by a low metallicity star like this progenitor star.
The companion star Gaia BH3, as old as the other one was, is about 76% the mass of the Sun and somewhat cooler, but about 10 times more luminous. It orbits the black hole on an elliptical path at a distance between about 4.5 times the distance between Earth and the Sun — a measure called an astronomical unit (AU) — and 29 Au. By comparison, Jupiter orbits about five AU from the Sun and Neptune about 30 AU.
“The most surprising result for me was the fact that the chemical composition of this companion star did not show anything special, so it was not affected by the black hole’s supernova explosion,” said study co-author Elisabetta Cafu.
This story was reported by Reuters.
