Discovery of Gaia BH2 and‍ Gaia BH3

Astronomers at⁤ teh University of Hawaiʻi Institute‍ for Astronomy (IfA) have pieced together the ‌dramatic history of a distant red‍ giant by studying subtle changes in its ‌light.⁤ Tiny fluctuations in brightness ‍reveal that the star may have collided⁢ and merged wiht another⁤ star long ago, ⁣a​ violent event that likely left it spinning much faster than normal. Today, this unusual star circles a quiet black hole ‍in a system known as Gaia BH2.

using⁢ observations from NASA’s Transiting Exoplanet Survey ⁤satellite (TESS), ⁣the team detected faint vibrations known as “starquakes” moving through the red giant, which ​is the companion ⁢to the ​black hole. Gaia BH2 itself was‌ first identified in 2023 by ​the European Space Agency’s Gaia ⁣mission. ‍Much​ like earthquakes ⁣help scientists explore Earth’s interior, these stellar​ vibrations provide insights ​into​ the star’s internal⁣ structure‌ and history. ‍ NASA details the TESS mission and its capabilities.

The ⁤research team also‍ investigated ⁢another ⁣similar system, ‍Gaia BH3, discovered using the same method. Interestingly,despite expectations of observing oscillations ⁢in Gaia BH3’s ⁤companion star,none were detected. This unexpected result⁣ suggests that current theories about stars with extremely low metal content may⁣ need to be revised. Space.com provides further⁢ details on the‌ Gaia ‌BH3 discovery.

Both Gaia ‍BH2 and Gaia ⁢BH3 belong to ​a class of dormant black hole systems. These black holes are not actively pulling in material from their companion stars, which means they‌ do not emit X-rays. Rather, astronomers discovered them by carefully tracking‌ the motion ⁤of nearby stars. these findings are changing how scientists ​search for and study black holes within the Milky Way. ⁢ ESA’s official announcement about the ‌Gaia discoveries.

Understanding Starquakes and⁢ Stellar Mergers

Starquakes, ⁣analogous to⁣ earthquakes on Earth, are non-radial oscillations ⁢- vibrations that cause a star‌ to change shape slightly.⁤ analyzing⁢ these⁤ vibrations allows astronomers to infer properties like the⁢ star’s mass, radius,⁣ and internal ‍structure. The ⁤observed starquakes in⁣ Gaia BH2’s companion star suggest a rapid rotation, a characteristic often associated with stars formed from​ a⁣ merger. Astronomy.com explains the concept of starquakes.

Stellar mergers are ​violent