'Starquakes' reveal young red giant orbiting dormant black hole
Astronomers have used "starquakes"—tiny vibrations inside stars—to uncover the surprising past of a red giant in the Gaia BH2 system.
This star is about five billion years old but has chemical traits usually seen in much older stars, making it a real oddball.
Starquakes and a spinning mystery
By studying these stellar quakes, researchers found the star spins much faster than expected for its age.
As lead author Daniel Hey put it, "Just like seismologists use earthquakes to study Earth's interior, we can use stellar oscillations to understand what's happening inside distant stars."
This rapid spin hints that the star might have merged with another or picked up extra material when its black hole companion formed.
Rethinking what we know about stars
The team also checked out another system, Gaia BH3, and noticed something was off—no starquakes where they expected them.
That means our current models for certain ancient stars might need an update.
All this helps scientists better understand how weird and wonderful stars can be as they evolve.