Astronomers Discover Second Largest Black Hole in Milky Way Galaxy

REPUBLIKA.CO.ID, JAKARTA – Astronomers found black hole with a mass about 33 times that of the Sun. The black hole is said to be the second largest known mass in the Milky Way Galaxy, after supermassive black hole which is hiding in the middle of the galaxy.

Quoted from the page Reuters, Monday (22/4/2024), the newly identified black hole is located about 2,000 light years from Earth. One light year is the distance that light travels in a year, or 9.5 trillion kilometers.

Cosmetically, it is relatively close, and precisely in the constellation known as Aquila. The black hole has a companion star orbiting it. The identification was made through observations made on the European Space Agency’s Gaia mission.

Black holes are very dense objects with such strong gravity that even light cannot escape, making them difficult to detect. The European Space Agency’s Gaia took the initiative to do a massive census.

Data from the European Southern Observatory’s Very Large Telescope based in Chile and other ground-based observatories were used to determine the size of the black hole. The identification results were also published in the journal //Astronomy & Astrophysics//.

“This black hole is not only very large, but also very strange in many aspects. It is really something we did not expect to see,” said the lead author of the study, Pasquale Panuzzo, an engineer researcher at the French CNRS research institute who works at the Observatoire. of Paris.

Panuzzo and his team named the black hole Gaia BH3, and this black hole falls into the category of stellar black holes, because it was “born” from the collapse of a star. One of the strange things is that the black hole moves in the galaxy in the opposite direction to the orbit of the stars in the Milky Way.

According to a team of astronomers, Gaia BH3 may have been formed after the death of a star more than 40 times the mass of the Sun. The original star Gaia BH3 is thought to be composed almost entirely of hydrogen and helium.

Stars in the early universe had a chemical composition known as low metallicity. This star was formed relatively early in the history of the universe, perhaps two billion years after the event // Big Bang //.

When the star explodes at the end of its life (known as a supernova phenomenon), a lot of material is ejected into space. Meanwhile, the remnants collapsed violently to form a black hole.

The discovery of Gaia BH3 is said to support the model of stellar evolution. The model shows that supermassive black holes can only be produced by stars with a low metal content like their parent star.

Meanwhile, Gaia’s companion star BH3 is expected to be as old as the other stars. It is about 76 percent the mass of the Sun and slightly cooler, but 10 times brighter. The companion star orbits the black hole in an elliptical path.

The distance has been observed to vary, between about 4.5 times the distance between Earth and the Sun and 29 astronomical units (AU). For comparison, Jupiter orbits about five AU from the Sun and Neptune orbits about 30 AU.

“The surprising result for me was that the chemical composition of this companion star did not show anything special, so it was not affected by the black hole supernova explosion,” said astronomer Observatoire de Paris and co-author of the study Elisabetta Coffee.