Dust loss from activated asteroid P/2015 X6

TL;DR

This study models dust emission from activated asteroid P/2015 X6, suggesting sustained dust loss likely caused by ice sublimation or rotational instability over a two-month period.

Contribution

First detailed dust tail modeling of P/2015 X6 indicating sustained activity and constraining dust parameters and activation timing.

Findings

Dust loss lasted over two months.

Dust particles ranged from 1 μm to 1 cm.

Total ejected mass estimated at 5-9×10^6 kg.

Abstract

We present observations and dust tail models of activated asteroid P/2015 X6 from deep imaging data acquired at the 10.4m Gran Telescopio Canarias (GTC) from mid-December 2015 to late January 2016. The results of the modeling indicate that the asteroid has undergone a sustained dust loss over a two-month or longer period. The dust parameters, derived from multidimensional fits of the available images, are compatible with either ice sublimation or rotational instability processes. An impulsive event, as it could be associated to an impact with another body, is less likely. A power-law distribution of particles, with minimum and maximum radius of 1 $\mu$m and 1 cm, and power index of --3.3 is found to be consistent with the observations. Depending on the ejection velocity model adopted, the particle velocities are found in the 0.3 to 10 m s$^{-1}$ range. The activation time was between 18-26 days before discovery. The total ejected mass from that time to the most recent observation is in the range 5-9$\times$10$^6$ kg. No dust features giving indication of past activity earlier than the activation time have been observed.