The end states of long-period comets and the origin of Halley-type comets

Julio A. Fernández, Tabaré Gallardo, Juan D. Young
(Submitted on 17 Jun 2016)

We analyze a sample of 73 old long-period comets (LPCs) (orbital periods 200 < P <1000 yr) with perihelion distances q<2.5 au, discovered in the period 1850-2014. We cloned the observed comets and also added fictitious LPCs with perihelia in the Jupiter’s zone. We consider both a purely dynamical evolution and a physico-dynamical one with different physical lifetimes. We can fit the computed energy distribution of comets with q<1.3 au to the observed one only within the energy range 0.01< x <0.04 au−1 (or periods 125< P<1000 yr), where the “energy” is taken as the inverse of the semimajor axis a, namely x≡1/a. The best results are obtained for physical lifetimes of about 200-300 revolutions (for a comet with a standard q=1 au). We find that neither a purely dynamical evolution, nor a physico-dynamical one can reproduce the long tail of larger binding energies ($x \gsim 0.04$ au−1) that correspond to most Halley-type comets (HTCs) and Jupiter-family comets. We conclude that most HTCs are not the end states of the evolution of LPCs, but come from a different source, a flattened one that we identify with the Centaurs that are scattered to the inner planetary region from the trans-Neptunian belt. These results also show that the boundary between LPCs and HTCs should be located at an energy x∼0.04 au−1 (P∼125 yr), rather than the conventional classical boundary at P=200 yr.

Comments: 34 pages, 17 figures, article in press
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference: Monthly Notices of the Royal Astronomical Society, 2016
Cite as: arXiv:1606.05603 [astro-ph.EP]
(or arXiv:1606.05603v1 [astro-ph.EP] for this version)
Submission history
From: Julio Angel Fernandez
[v1] Fri, 17 Jun 2016 17:45:41 GMT (1103kb,D)
http://arxiv.org/abs/1606.05603