The recently discovered object P/2019 LD2 (ATLAS) was initially thought to be a Jupiter Trojan asteroid, until dynamical studies and the appearance of cometary activity revealed that this object is actually an active Centaur. However, the dynamical history, thermal environment, and impact of such environments on the activity of 2019 LD2 are poorly understood. Here we conduct dynamical simulations to constrain its orbital history and resulting thermal environment over the past 3000 years. We find that 2019 LD2 is currently in the dynamical “Gateway” that facilitates the majority of transitions from the Centaur population into the Jupiter Family of Comets (JFC population; Sarid et al. 2019). Our calculations show that it is unlikely to have spent significant amounts of time in the inner solar system, suggesting that its nucleus is relatively pristine in terms of physical and chemical processing through its history. This could explain its relatively high level of distant activity as a recently activated primordial body. Finally, whereas an object larger than ~1 km in radius evolves from the Gateway into the Jupiter Family Comet (JFC) population with a median frequency of once every ~2.7 years; an object larger than ~3 km in radius makes this transition with a median frequency of once every ~73 years. Forward modeling of 2019 LD2 shows that it will transition into the JFC population in 2063, representing the first known opportunity to observe the evolution of an active Centaur nucleus as it experiences this population-defining transition.
|Original language||English (US)|
|State||Published - Aug 6 2020|
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