Astronomers Expected Hundreds of Two-Sun Planets, but Only Found 14, Einstein’s Theory May Explain Why
The Daily Galaxy • • science
Key Points:
- Despite the commonality of binary stars and planet formation, only 14 out of over 6,000 confirmed exoplanets orbit two stars, far fewer than the hundreds expected, highlighting a puzzling gap in observations.
- The scarcity is especially pronounced around tight binary star systems with orbital periods under seven days, where no planets have been detected, creating a "desert" of circumbinary planets.
- Research suggests that general relativity causes orbital precession differences between stars and planets in these systems, leading to a resonance that destabilizes planetary orbits, resulting in about 80% of such planets being ejected or lost.
- An instability zone around binary stars further contributes to planet loss, as planets with increasingly eccentric orbits enter this region and are gravitationally cleared out by three-body effects.
- The circumbinary planets observed tend to orbit just outside this instability boundary, indicating they likely formed farther away and migrated inward until reaching the edge of orbital stability.
