Note on the dynamical evolution of C/2017 K2 PANSTARRS

TL;DR

This study analyzes the past and future orbital evolution of comet C/2017 K2 to determine its dynamical history, revealing it is a long-period comet that has previously visited the inner solar system.

Contribution

It provides a detailed dynamical analysis of C/2017 K2, including backward and forward orbit propagation considering Galactic and stellar perturbations, establishing its status as a dynamically old Oort spike comet.

Findings

C/2017 K2 is a dynamically old Oort spike comet.

It has previously visited within 10 au of the Sun.

It will approach perihelion in December 2022.

Abstract

(Abreviated) Comet C/2017 K2 PANSTARRS drew attention to its activity already at a time of its discovery in May 2017 when it was about 16 au from the Sun. This Oort spike comet will approach its perihelion in December 2022, and the question about its dynamical past is one of the important issues to explore. To this aim it is necessary to obtain its precise osculating orbit, its original orbit, and propagate its motion backwards in time to the previous perihelion. We study a dynamical evolution of C/2017 K2 to the previous perihelion (backward calculations for about 3-4 Myr) as well as to the future (forward calculations for about 0.033 Myr). Outside the planetary system both Galactic and stellar perturbations were taken into account. We derived that C/2017 K2 is a dynamically old Oort spike comet (1/a$_{prev}$ = (48.7 $\pm$ 7,9) x10$^{-6}$ au$^{-1}$) with the previous perihelion distance below 10 au for 97 per cent of VCs (nominal q$_{prev}$ = 3.77 au). It means that C/2017 K2 has already visited our planetary zone during its previous perihelion passage. Thus, it is almost certainly a dynamically old Oort spike comet.