Where do long-period comets come from? Moving through Jupiter-Saturn barrier

TL;DR

This study analyzes the dynamical evolution of 64 long-period comets, revealing their origins, classifications, and motion through the Jupiter-Saturn barrier, with implications for understanding their source pathways.

Contribution

It provides a homogeneous set of orbits, determines non-gravitational effects for the first time in some comets, and offers new insights into their source regions and pathways.

Findings

Approximately 50% of comets had previous perihelion distances below 15 au.

Classified 31 comets as dynamically new, 26 as dynamically old, and 7 as uncertain.

Demonstrated motion through the Jupiter-Saturn barrier with some comets having smaller previous perihelion distances.

Abstract

Past and future dynamical evolution of all 64 long period comets having 1/aori< 1\times10-4 au-1 and qosc > 3.0 au and discovered after 1970 is studied. For all of them we obtained a new, homogeneous set of osculating orbits, including 15 orbits with detected non-gravitational parameters. The non-gravitational effects for eleven of these 15 comets have been determined for the first time. These were propagated numerically back and forth up to the 250 au heliocentric distance, constituting sets of original and future orbits together with their uncertainties. Next we followed the dynamical evolution under the Galactic tides for one orbital revolution to the past and future, obtaining orbital elements at previous/next perihelion passages. We obtained a clear dependence of the last revolution change in perihelion distance with respect to the 1/aori, what confirmed theoretical expectations. We show that about 50 per cent of all investigated comets have their previous perihelion distance below the 15 au limit. This resulted in classifying 31 comets as dynamically new, 26 as dynamically old and 7 having unclear status. We also present several examples of cometary motion through the Jupiter-Saturn barrier, some of them with the previous perihelion distance smaller than the observed one. New interpretations of the long period comets source pathways are also discussed in the light of suggestions of Kaib & Quinn (2009).