Investigating the flyby scenario for the HD 141569 system

TL;DR

This study investigates whether a flyby encounter could explain the observed features of the HD 141569 system's debris disk, using analytical and numerical methods to test different scenarios and parameters.

Contribution

It presents a comprehensive analysis of the flyby scenario for HD 141569, considering multiple variants and providing constraints on the encounter parameters based on observations.

Findings

A flyby with one planet best reproduces disk morphology.

Periapsis passage likely occurred 5000-8000 years ago at 600-900 AU.

Certain planet masses and eccentricities are compatible with observed disk features.

Abstract

HD 141569, a triple star system, has been intensively observed and studied for its massive debris disk. It was rather regarded as a gravitationally bound triple system but recent measurements of the HD 141569A radial velocity seem to invalidate this hypothesis. The flyby scenario has therefore to be investigated to test its compatibility with the observations. We present a study of the flyby scenario for the HD141569 system, by considering 3 variants: a sole flyby, a flyby associated with one planet and a flyby with two planets. We use analytical calculations and perform N-body numerical simulations of the flyby encounter. The binary orbit is found to be almost fixed by the observational constraint on a edge-on plane with respect to the observers. If the binary has had an influence on the disk structure, it should have a passing time at the periapsis between 5000 and 8000 years ago and a distance at periapsis between 600 and 900 AU. The best scenario for reproducing the disk morphology is a flyby with only 1 planet. For a 2 Mj (resp. 8 Mj) planet, its eccentricity must be around 0.2 (resp. below 0.1). In the two cases, its apoapsis is about 130 AU. Although the global disk shape is reasonably well reproduced, some features cannot be explain by the present model and the likehood of the flyby event remains an issue. Dynamically speaking, HD 141569 is still a puzzling system.