Astronomers Uncover Milky Way's Second-Largest Black Hole, Gaia BH3

Astronomers uncover the second-largest black hole in the Milky Way, Gaia BH3, challenging our understanding of stellar evolution and opening new avenues for studying dormant black holes.

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Aqsa Younas Rana
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Astronomers Uncover Milky Way's Second-Largest Black Hole, Gaia BH3

Astronomers Uncover Milky Way's Second-Largest Black Hole, Gaia BH3

Astronomers have uncovered the second-largest known black hole in the Milky Way galaxy, named Gaia BH3. This massive black hole, located approximately 2,000 light-years from Earth in the constellation Aquila, has a mass 33 times greater than the Sun and is orbiting a companion star.

The uncovering of Gaia BH3 was made possible by the European Space Agency's Gaia mission, which precisely determined the positions of stars and enabled scientists to grasp the orbit of the black hole and estimate its mass. Follow-up observations using the European Southern Observatory's Very Large Telescope and other ground-based observatories confirmed the black hole's extraordinary size.

Gaia BH3 is the largest stellar black hole found in our galaxy to date, surpassing the previous record holder, Cygnus X-1, which has a mass of about 21 solar masses. While Gaia BH3 is the most massive stellar black hole in the Milky Way, it is still dwarfed by the supermassive black hole at the center of our galaxy, Sagittarius A*, which has a mass of approximately 4 million Suns.

Why this matters: The uncovering of Gaia BH3 challenges our understanding of how massive stars develop and evolve, as black holes of this size were previously only found in distant galaxies through gravitational waves. This finding showcases the transformational impact of the Gaia mission on astronomy and astrophysics, opening up new avenues for studying the formation and evolution of stellar black holes in our cosmic neighborhood.

Astronomers believe that Gaia BH3 likely formed from the collapse of a low-metallicity star that was more than 40 times as massive as the Sun. The black hole's companion star, which is about 76% the mass of the Sun and slightly cooler but 10 times more luminous, supports stellar evolution models that show massive stellar black holes can only be produced by stars with low metal content.

Gaia BH3 is considered a dormant black hole, as it is not actively accreting matter from its companion star. The black hole was detected through its gravitational influence on the companion star's motion, causing a noticeable wobble that was observed by the Gaia spacecraft. This detection method opens up the possibility of uncovering more inactive black holes in the Milky Way that have remained hidden until now.

The Gaia mission has also identified two other inactive black holes in the Milky Way, named Gaia BH1 and Gaia BH2. These uncoverings highlight the potential for finding more dormant black holes in our galaxy and provide valuable insights into the population and distribution of these enigmatic objects.

Astronomers are excited about the prospects of further studying Gaia BH3 and its companion star to unravel more details about the black hole's history and properties. As Kareem El-Badry, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute for Astronomy, stated, "This is the kind of uncovering that happens once in a researcher's lifetime.

Key Takeaways

  • Astronomers discovered 2nd-largest black hole in Milky Way, named Gaia BH3.
  • Gaia BH3 has a mass 33 times greater than the Sun and orbits a companion star.
  • Gaia BH3 is the largest stellar black hole found in our galaxy, surpassing Cygnus X-1.
  • Gaia BH3 likely formed from the collapse of a low-metallicity star over 40 times the Sun's mass.
  • Gaia mission's detection method enables finding more inactive black holes in the Milky Way.