Complex sentence: The asteroid orbits the Sun at a distance of 2.3--2.6 AU once every 3 years and 9 months (1,374 days) and stays in a 2:1 orbital resonance with the planet Mars.
Split into simpler sentences: The asteroid orbits the Sun at a distance of 2.3--2.6 AU once every 3 years and 9 months. It has a 2:1 orbital resonance with the planet Mars.