English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report on the characterisation of the dust activity and dynamicalevolution of two faint active asteroids, P/2019 A4, and P/2021 A5, observedwith the 10.4m GTC using both imaging and spectroscopy. Asteroid P/2019 A4activity is found to be linked to an impulsive event occurring some $\pm$10days around perihelion, probably due to a collision or a rotational disruption.Its orbit is stable over 100 Myr timescales. Dust tail models reveal ashort-term burst producing (2.0$\pm$0.7)$\times$10$^6$ kg of dust for maximumparticle radius rmax=1 cm. The spectrum of P/2019 A4 is featureless, andslightly redder than the Sun. P/2021 A5 was active $\sim$50 days afterperihelion, lasting $\sim$5 to $\sim$60 days, and ejecting(8$\pm$2)$\times$10$^6$ kg of dust for rmax=1 cm. The orbital simulations showthat a few percent of dynamical clones of P/2021 A5 are unstable on 20-50 Myrtimescales. Thus, P/2021 A5 might be an implanted object from the JFC region orbeyond. These facts point to water ice sublimation as the activation mechanism.This object also displays a featureless spectrum, but slightly bluer than theSun. Nuclei sizes are estimated in the few hundred meters range for bothasteroids. Particle ejection speeds ($\sim$0.2 m/s) are consistent with escapespeeds from those small-sized objects.

Dust environment of active asteroids P/2019 A4 (PANSTARRS) and P/2021 A5 (PANSTARRS)