Astronomers discover largest black hole in Milky Way
WASHINGTON: Astronomers have discovered a black hole with a mass about 33 times greater than that of our sun, the biggest one known in the Milky Way aside 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 cosmic terms - in the constellation Aquila, and has a companion star orbiting it, researchers said on Tuesday. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
Black holes are extraordinarily dense objects with gravity so strong that not even light can escape, making it difficult to spot them. This one was identified through observations made in the European Space Agency’s Gaia mission, which is creating a huge stellar census, because it caused a wobbling motion in its companion star. Data from the European Southern Observatory’s Chile-based Very Large Telescope and other ground-based observatories were used to verify the black hole’s mass.
“This black hole is not only very massive, it is also very peculiar in many aspects. It is really something we never expected to see,” said Pasquale Panuzzo, a research engineer at the French research agency CNRS working at the Observatoire de Paris and lead author of the study published in the journal Astronomy & Astrophysics.
For instance, the black hole, called Gaia BH3, and its companion are traveling within the galaxy in the opposite direction of how stars typically orbit in the Milky Way.
Gaia BH3 probably formed ater the death of a star that was more than 40 as massive as the sun, the researchers said.
Black holes that result from the collapse of a single star are called stellar black holes. Gaia BH3 is the largest-known stellar black hole, according to astronomer and study coauthor Tsevi Mazeh of the Tel Aviv University in Israel.
Stellar black holes are dwarfed in size by the supermassive black holes inhabiting the center of most galaxies. One such black hole called Sagitarius A*, or Sgr A*, is located at the heart of the Milky Way. It possesses 4 million times the mass of our sun and is located about 26,000 light-years from Earth.
Gaia BH3’S progenitor star was composed almost entirely of hydrogen and helium. Stars in the early universe had such a chemical composition, known as low metallicity.