* Astronomy

Title: The Hungaria Asteroids: resonances, close encounters and impacts with terrestrial planets
Authors: Mattia Alvise Galiazzo, Ákos Bazsó, Rudolf Dvorak

The Hungaria asteroid family, which consists of more than 8000 members with semi-major axes between 1.78 and 2.03 AU, is regarded as one source for Near-Earth Asteroids. Named after (434) Hungaria these asteroids are relatively small (mean diameter \sim 1 km) and have inclinations of the order of 20°. They are mainly perturbed by Jupiter and Mars, and are ejected because of mean motion and secular resonances with these planets and then become Mars-crossers; later they may even cross the orbits of Earth and Venus. We are interested to analyse the close encounters and possible impacts with these planets.
For 200 selected objects which are on the edge of the group we integrated their orbits over 100 million years in a simplified model of the planetary system (Mars to Saturn) subject to only gravitational forces.
We picked out a sample of 11 objects (each with 50 clones) with large variations in semi-major axis and restarted the numerical integration in the model Venus to Saturn. Due to close encounters in connection with mean motion and secular resonances some of them achieve high inclinations and eccentricities which then leads to relatively high velocity impacts on Venus, Earth, and Mars. We report all close encounters and impacts with the terrestrial planets and statistically determine collision velocities of these fictitious Hungarias. With this data we compute the effect of the possible impacts with the terrestrial planets and estimate the diameter of the crater depending on the impact energy released, the impact velocity and the impact angle.

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