Abstract
Rotational spin-up due to outgassing of comet nuclei has been identified
as a possible mechanism for considerable mass-loss and splitting. We
report a search for spin changes for three large Jupiter-family comets
(JFCs): 14P/Wolf, 143P/Kowal-Mrkos, and 162P/Siding Spring. None of the
three comets has detectable period changes, and we set conservative
upper limits of 4.2 (14P), 6.6 (143P) and 25 (162P) minutes per orbit.
Comparing these results with all eight other JFCs with measured
rotational changes, we deduce that none of the observed large JFCs
experiences significant spin changes. This suggests that large comet
nuclei are less likely to undergo rotationally-driven splitting, and
therefore more likely to survive more perihelion passages than smaller
nuclei. We find supporting evidence for this hypothesis in the
cumulative size distributions of JFCs and dormant comets, as well as in
recent numerical studies of cometary orbital dynamics. We added 143P to
the sample of 13 other JFCs with known albedos and phase-function
slopes. This sample shows a possible correlation of increasing
phase-function slopes for larger geometric albedos. Partly based on
findings from recent space missions to JFCs, we hypothesise that this
correlation corresponds to an evolutionary trend for JFCs. We propose
that newly activated JFCs have larger albedos and steeper phase
functions, which gradually decrease due to sublimation-driven erosion.
If confirmed, this could be used to analyse surface erosion from ground
and to distinguish between dormant comets and asteroids.
Original language | English |
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Journal | Monthly Notices of the Royal Astronomical Society, Advance Access |
Early online date | 11 Jun 2018 |
DOIs | |
Publication status | Early online date - 11 Jun 2018 |
Keywords
- comets: general
- comets: individual