# Whiskered parabolic tori in the planar $(n+1)$-body problem

## TL;DR

This paper proves the existence of special solutions in the planar (n+1)-body problem where one body escapes to infinity with zero velocity, related to whiskered parabolic tori at infinity, expanding understanding of long-term dynamics.

## Contribution

It introduces a general theorem on parabolic tori and demonstrates their existence in the planar (n+1)-body problem, revealing new types of asymptotic motions.

## Key findings

- Existence of solutions tending to parabolic motion with one body escaping to infinity.
- Introduction of a theorem on parabolic tori with stable and unstable manifolds at infinity.
- Application to skew product maps with parabolic tori, generalizing Takens and Voronin results.

## Abstract

The planar $(n+1)$-body problem models the motion of $n+1$ bodies in the plane under their mutual Newtonian gravitational attraction forces. When $n\ge 3$, the question about final motions, that is, what are the possible limit motions in the planar $(n+1)$-body problem when $t\to \infty$, ceases to be completely meaningful due to the existence of non-collision singularities. In this paper we prove the existence of solutions of the planar $(n+1)$-body problem which are defined for all forward time and tend to a parabolic motion, that is, that one of the bodies reaches infinity with zero velocity while the rest perform a bounded motion. These solutions are related to whiskered parabolic tori at infinity, that is, parabolic tori with stable and unstable invariant manifolds which lie at infinity. These parabolic tori appear in cylinders which can be considered `normally parabolic'. The existence of these whiskered parabolic tori is a consequence of a general theorem on parabolic tori developed here. Another application of our theorem is a conjugation result for a class of skew product maps with a parabolic torus with its normal form generalizing results of Takens and Voronin.