Jupiter: friend or foe? IV: The influence of orbital eccentricity and inclination

Horner, J. and Jones, B. W. (2012) Jupiter: friend or foe? IV: The influence of orbital eccentricity and inclination. International Journal of Astrobiology, 11 (3). pp. 147-156. ISSN 1473-5504

Abstract

For many years, it has been assumed that Jupiter has prevented the Earth from being subject to a punishing impact regime that would have greatly hindered the development of life. Here, we present the fourth in a series of dynamical studies investigating this hypothesis. In our earlier work, we examined the effect of Jupiter's mass on the impact rate experienced by the Earth. Here, we extend that approach to consider the influence of Jupiter's orbital eccentricity and inclination on the impact rate from asteroidal bodies and short-period comets. We first considered scenarios in which Jupiter's orbital eccentricity was somewhat higher and somewhat lower than that in our Solar System, for a variety of ẫJupiterâ™ masses. We find that Jupiter's orbital eccentricity plays a moderate role in determining the impact flux at Earth, with more eccentric orbits resulting in a noticeably higher impact rate of asteroids than is the case for more circular orbits. This is particularly pronounced at high 'Jupiter' masses. For the short-period comets, the same effect is clearly apparent, albeit to a much lesser degree. The flux of short-period comets impacting the Earth is slightly higher for more eccentric Jovian orbits. We also considered scenarios in which Jupiter's orbital inclination was greater than that in our Solar System. Increasing Jupiter's orbital inclination greatly increased the flux of asteroidal impactors upon the Earth. However, at the highest tested inclination, the disruption to the Asteroid belt was so great that the belt would be entirely depleted after an astronomically short period of time. In such a system, the impact flux from asteroid bodies would therefore be very low, after an initial period of intense bombardment. By contrast, the influence of Jovian inclination on impacts from short-period comets was very small. A slight reduction in the impact flux was noted for the moderate and high inclination scenarios considered in this work-the results for inclinations of 5° and 25° were essentially identical.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2012 Cambridge University Press. Published version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 26 Jun 2014 04:16
Last Modified: 22 Mar 2017 01:44
Uncontrolled Keywords: centaurs; comets; minor planets; planets and satellites; solar system formation
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020109 Space and Solar Physics
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020101 Astrobiology
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1017/S1473550412000043
URI: http://eprints.usq.edu.au/id/eprint/25368

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