The Solar System's Post-Main Sequence Escape Boundary

TL;DR

This paper investigates how the Sun's mass loss during its post-main sequence evolution affects the stability of orbiting bodies, identifying a critical distance beyond which objects are likely to escape the Solar System.

Contribution

The study quantifies the critical semimajor axis for orbital stability during stellar mass loss, providing insights into the fate of distant Solar System objects and exoplanetary systems.

Findings

Critical semimajor axis for bound objects is approximately 1,000 to 10,000 AU.

Objects near or beyond this boundary have a high likelihood of escape.

Survival of distant objects like the Oort Cloud depends on their orbital phase during stellar evolution.

Abstract

The Sun will eventually lose about half of its current mass nonlinearly over several phases of post-main sequence evolution. This mass loss will cause any surviving orbiting body to increase its semimajor axis and perhaps vary its eccentricity. Here, we use a range of Solar models spanning plausible evolutionary sequences and assume isotropic mass loss to assess the possibility of escape from the Solar System. We find that the critical semimajor axis in the Solar System within which an orbiting body is guaranteed to remain bound to the dying Sun due to perturbations from stellar mass loss alone is approximately 1,000 AU - 10,000 AU. The fate of objects near or beyond this critical semimajor axis, such as the Oort Cloud, outer scattered disc and specific bodies such as Sedna, will significantly depend on their locations along their orbits when the Sun turns off of the main sequence. These results are applicable to any exoplanetary system containing a single star with a mass, metallicity and age which are approximately equal to the Sun's, and suggest that few extrasolar Oort Clouds could survive post-main sequence evolution intact.