Re-examination of the transportation abilities of the 5:2 MMR with Jupiter

Resonances in the main asteroid belt play a significant role in dynamical evolution of small bodies in the Solar system. They are capable of driving objects into near-Earth object (NEO) region as well.

 

This work re-examines the transportation abilities of 5:2 mean motion resonance (MMR) with Jupiter. We focus on a greater portion of the resonance than in the previous study [1] that used a similar method. Firstly, short-term FLI (fast Lyapunov indicator [2]) maps of 5:2 MMR were computed in order to distinguish between stable and unstable orbits. Then over 10 000 unstable particles were selected and integrated for a longer period of time, up to 10 Myr, to reveal the transportation abilities of the resonance. We are interested in an elimination course along perihelion distance q = 0.26 au that was discovered previously [1]. Moreover, we also search for the orbits of potentially hazardous asteroids (PHAs) and for orbits that correspond to recent L chondrite meteorites with pedigree, because various studies suggest an association of this resonance with some known PHAs and shocked fossil L chondrites [3-7].

 

Our results in some aspects correspond to the results of [1]. For example, according to our simulation, 99.45% of test particles became NEOs at some point during the integration, which is much more than what was found in the older studies. However, this can be attributed to the method that was used in [1] and this work. Nevertheless, there are also many different results. For example, we obtained considerably smaller amount of particles reaching a < 1 au, although this amount is still considerably greater than in older studies. We also registered very large number (~ 36.19%) of Sun-grazing particles, i.e. particles that reached perihelion distance q < 0.016 au. In our simulation, the vast majority (92.8%) of test particles entered the Hill sphere of the Earth. The amount of particles that got as close to the orbit of Earth as PHAs was, of course, even larger (97.45%). This large amount, in conjunction with the result of [8] that the 5:2 MMR contributes to the NEO population primarily at larger sizes, led us to search for orbits corresponding to the known PHAs. We considered the list of all 2 374 known PHAs. According to our simulation, the orbits of 17 known PHAs were recovered by at least 70% of the test particles at some point. We also searched for heliocentric orbits of recent L chondrite meteorites among test particles in our simulation. Only in the case of the Porangaba and Park Forest meteorites did more than 10% of test particles recover their orbit at some point during the integration. The final distribution of test particles in our simulation revealed that ejections to hyperbolic orbits or to orbits with a > 100 au were predominantly caused by Jupiter, as was expected. Unfortunately, our simulation did not confirm the existence of a removal course along q = 0.26 au. We also tried to repeat the procedures of [1] while using different software, to see if we were able to obtain ejections along q = 0.26 au. However, our attempts were not successful. Our results suggest that there is some kind of discrepancy between using the MERCURIUS integrator (REBOUND package [9]) and the ORBIT9 integrator (OrbFit package [10]). This subject is worth additional examination.

 

Acknowledgements:

This work was supported by the VEGA - the Slovak Grant Agency for Science, grant No. 2/0009/22.

 

References:

[1] Todorović N., 2017, MNRAS, 465, 4441

[2] Skokos C., Gottwald G. & Laskar J., 2016, Chaos detection and predictability (Chapter 2)

[3] de León J., Campins H., Tsiganis K., et al., 2010, A&A, 513, A26

[4] Nedelcu D.A., Birlan M., Popescu M., et al., 2014, A&A, 567, L7

[5] Nesvorný D., Vokrouhlický D., Morbidelli A. & Bottke W.F., 2009, Icarus, 200, 698

[6] Simms M., 2021, Geology Today, 37, 225

[7] Todorović N., 2018, MNRAS, 475, 601

[8] Granvik M.,  Morbidelli A., Jedicke R., et al., 2018, Icarus, 312, 181

[9] REBOUND (https://rebound.readthedocs.io/en/latest/)

[10] OrbFit (http://adams.dm.unipi.it/orbfit/)