Oort Cloud Comets: Perturbations Due to the Passage of Gliese 710

Abstract

The outermost region of the Solar System is called Oort cloud which is the Solar systems’ reservoir of long-period comets that extends to distances up to 200 000 au from the Sun. Long-period comets can be injected towards the inner Solar System due to galactic tides and passing stars. While galactic tides are effective on long time scales, perturbations of stellar flybys are short-term effects that have not only occurred in the past. Gaia observations confirmed that the solar system will experience a close flyby of the K-type star Gliese 710 in about 1.3 Myrs. This star will probably pass at a distance of about 10500 au to the Sun. When crossing the Oort cloud this 0.6 solar mass star will perturb the long-period comets especially those objects that are close to Gliese 710’s trajectory. In this numerical investigation, we use our recently developed GPU based N-body code GANBISS and study the orbits of some hundred million test-comets for the time of the stellar flyby which takes about 64000 years. The simulations show that the stellar passage generates cometary streams - which either transport comets into the inner solar system or scatter a huge amount of comets into interstellar space.