According to a paper by Eva Lilly, a Senior Scientist at the Planetary Science Institute, Centaurs can exhibit comet-like activity due to a rapid reshaping of their orbits caused by a close encounter with Jupiter or Saturn.
“We have discovered why some Centaurs behave like comets while others remain as quiet asteroids, which has been a long-standing mystery. It didn’t make sense because there was no correlation with size, color, or orbit types,” said Lilly, who is the lead author of the paper titled “Semi-major Axis Jumps as the Activity Trigger in Centaurs and High-Perihelion Jupiter Family Comets,” published in the Astrophysical Journal Letters. Co-authors of the paper include PSI Scientists Kat Volk, Jordan Steckloff, and Henry Hsieh.
“In our research, we examined the dynamical history of all known Centaurs, both active and inactive, and combined our findings with thermal modeling. We aimed to identify a common pattern among active Centaurs that was absent in the inactive ones. Mapping the dynamical history of Centaurs is challenging because they orbit in the vicinity of giant planets, and their orbital evolution is influenced by the chaotic gravitational pull of these giants,” explained Lilly.
“To study this, we used a numerical integrator, a code that can predict the evolution of a celestial body’s orbit. However, for Centaurs, this can only be accurately known for a limited period, typically a few hundred years, due to the chaotic nature of their orbits. We discovered that all active Centaurs experienced a close encounter with either Jupiter or Saturn, resulting in a significant orbital change, which we refer to as the ‘a-jump.’
2024-01-10 03:00:05
Link from phys.org rnrn
