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 μm 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 5-9×106 kg. No dust features giving indication of
past activity earlier than the activation time have been observed.Comment: Accepted by ApJ, May 15th 201
