IAA authors:
Moreno, Fernando;Guirado, Daniel
Authors:
Moreno, Fernando;Licandro, Javier;Cabrera-Lavers, Antonio;Morate, David;Guirado, Daniel
Journal:
Monthly Notices of the Royal Astronomical Society
Abstract:
We report on the characterization of the dust activity and dynamical evolution of two faint active asteroids, P/2019 A4, and P/2021 A5, observed with the 10.4 m GTC using both imaging and spectroscopy. Asteroid P/2019 A4 activity is found to be linked to an impulsive event occurring some ±10 d around perihelion, probably due to a collision or a rotational disruption. Its orbit is stable over 100 Myr time-scales. Dust tail models reveal a short-term burst producing (2.0 ± 0.7) × 10<SUP>6</SUP> kg of dust for maximum particle radius r<SUB>max</SUB> = 1 cm. The spectrum of P/2019 A4 is featureless, and slightly redder than the Sun. P/2021 A5 was active ~50 d after perihelion, lasting ~5 to ~60 d, and ejecting (8 ± 2) × 10<SUP>6</SUP> kg of dust for r<SUB>max</SUB> = 1 cm. The orbital simulations show that a few percent of dynamical clones of P/2021 A5 are unstable on 20-50 Myr time-scales. Thus, P/2021 A5 might be an implanted object from the JFC region or beyond. These facts point to water-ice sublimation as the activation mechanism. This object also displays a featureless spectrum, but slightly bluer than the Sun. Nuclei sizes are estimated in the few hundred meters range for both asteroids. Particle ejection speeds (≍0.2 m s<SUP>-1</SUP>) are consistent with escape speeds from those small-sized objects.
URL:
https://ui.adsabs.harvard.edu/#abs/2021MNRAS.506.1733M/abstract
Keywords:
Minor planets;asteroids: individual: P/2019 A4P/2021 A5;Astrophysics - Earth and Planetary Astrophysics