New study says the Sun's dying eruptions could destabilize planets far sooner

A new paper in The Astrophysical Journal Letters models the Sun’s final evolutionary phase, finding that mass loss will occur in thousands of uneven bursts rather than a smooth flow. Each burst, equivalent to about one ten-thousandth of the Sun’s mass, imparts a small thrust that gradually shifts the Sun’s velocity and perturbs planetary trajectories. Over time, these perturbations increase orbital eccentricities, causing the outer planets to interact gravitationally, cross orbits, and in many simulations be expelled from the solar system.

The researchers ran 700 simulations, with nearly 80% showing chaotic orbital rearrangements shortly after the Sun has lost just 10% of its mass. While the inner planets will be engulfed by the Sun’s red-giant phase in five to six billion years, the outer planets could be scattered much earlier, potentially creating free-floating “rogue” planets. The findings also suggest that such violent endings may explain the abundance of rogue planets observed drifting between stars.