In addition, we estimate the contribution of the Centaurs to the NEOs, potential hazardous objects (PHOs), and short period comets (SPCs). Sections 3.2 and 3.3 show the statistical analysis and the results on close encounters (CEs) and the impact probability, interactions with the TPs, as well as a brief overview of interactions with the giant planets. The results are given in Section 3: the source regions of the impactors are described in Section 3.1. Section 2 describes the population sample, the tools to analyse the sample, and how the analysis was made. Some past works have already attempted to compute this rate, but none of them considered the entire Centaurs population, e.g. 2013), meaning after the Late Heavy Bombardment (ii) find the typical orbits of the Centaur impactors and (iii) determine from which sub-region of the Centaurs the impactors come from. This work aims to (i) constrain the rate of impacts on the TPs for the entire Centaur population in the recent solar system (after 3.8 Gyr ago Hartmann et al. All this material can be delivered to the planets via impacts and become important for their atmospheres and have astrobiological implications. Some former comets that had performed many passages in the inner solar system could also have exhausted part of their water content and thus can be considered as hydrated asteroids, very likely of type C, D, or P (Barucci, Fulchignoni & Lazzarin 1996). Thus, it is crucial to understand their orbital evolution, since it might end in a collision with one of the terrestrial planets (TPs) and lead to catastrophic events. These bodies are one of the main sources of Near-Earth Objects (NEOs). Centaurs have a short lifetime compared to the main belt asteroids (MBAs), and are typically removed from the solar system on time-scales of only a few millions of years (Di Sisto, Brunini & de Elía 2010 Galiazzo, Wiegert & Aljbaae 2016). This is because objects coming into the inner solar system from beyond Neptune can become comets more often than asteroids in the main belt and as such should be consistent with volatile material. They are generally thought as a by-product or an evolutionary product of the Trans-Neptunian objects, and thus should have generally lower density than the main belt bodies. There is the lack of general agreement among various definitions thus, in this paper we will consider Centaurs as objects with a semimajor axis ranging from 5.5 to 30 au. Only 53 per cent of the Centaurs can enter into the terrestrial planet region and ∼7 per cent can interact with terrestrial planets.Ĭelestial mechanics, minor planets, asteroids: general 1 INTRODUCTIONĬentaurs are objects in the solar system, with their orbits situated between those of the giant planets. >1 km), the impact frequency is one every 14.4 Myr for the Earth, 13.1 Myr for Venus, and 46.3 for Mars in the recent solar system. For an average impactor size of ∼12 km in diameter, the average impact frequency since the Late Heavy Bombardment is one every ∼1.9 Gyr for the Earth and 2.1 Gyr for Venus.
While crater sizes could extend up to hundreds of kilometres in diameter, given the presently known population of Centaurs the majority of the craters would be less than ∼10 km in all the planets. We also found subregions of the Centaurs where the possible impactors originate from. We compute the approximate amount of water released on the Earth, which is about 10 −5 of the total water present now.
We also estimate the possible crater sizes. We study the orbital evolution of the Centaurs toward the inner solar system and estimate the number of close encounters and impacts with the terrestrial planets after the Late Heavy Bombardment, assuming a steady-state population of Centaurs. Thus, it is crucial to understand their orbital evolution which in some cases might end in collision with terrestrial planets and produce catastrophic events. Originating mainly from the Trans-Neptunian objects, Centaurs represent one of the sources of Near-Earth Objects. Centaurs are solar system objects with orbits situated among those of the giant planets.
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