Scientists discovered a red giant star orbiting black hole in the Gaia BH2 system

Red giant star orbiting a quiet black hole in the Gaia BH2 system (Image: ESO/L. Calçada/Space Engine)

Astronomers decoded a red giant’s past around a quiet black hole. Subtle vibrations reveal clues about its age and evolution. The findings challenge assumptions about stellar chemistry and black-hole companions.

Star System Under Study

The researchers focus on Gaia BH2, a distant star-black hole system. The team is from the University of Hawaiʻi Institute for Astronomy (IfA). They used NASA’s TESS satellite to monitor tiny brightness oscillations.

Reason Behind the Study

Scientists wanted to understand stars orbiting “quiet” black holes. Gaia BH2 emits almost no radiation from its black hole. The goal is to reconstruct the star’s history using internal vibrations.

Major Scientific Observations Made

The red giant exhibited starquakes, oscillations revealing interior structure. Chemically “old” (alpha-rich), the star is only 5 billion years old. It rotates unusually fast every 398 days which hint towards past mergers. The observations of Gaia BH3 showed no oscillations, suggesting models need refining.

Implications For Astrophysics Research

Chemical composition alone may mislead age estimates. Asteroseismology proves powerful for decoding stellar evolution. The study may reshape how astronomers identify black hole companions.

Future Directions For Research

The researchers will study more red giants near quiet black holes. They want to understand how these stars rotate and evolve. They will also investigate past mergers with other stars.

Future observations using TESS will track tiny brightness changes. Spectroscopic data will show the stars’ composition and motion. Together, these studies will reveal how stars interact with black holes.