Activity of (2060) Chiron possibly caused by impacts?

TL;DR

This study investigates the activity of centaur 95P/(2060) Chiron, suggesting impacts and debris fallback as potential causes, supported by photometric variability, rotational light curves, and a detected tail indicating possible ring presence.

Contribution

It provides observational evidence supporting impact-induced activity and the existence of rings around Chiron, challenging previous assumptions about its mass-loss mechanisms.

Findings

Photometric scatter suggests microactivity possibly from debris fallback.

Rotational light curves support the presence of rings.

Detection of a 5 arcsec tail indicates possible ring or debris activity.

Abstract

The centaur 95P/(2060) Chiron is showing comet-like activity since its discovery, but the mass-loss mechanisms triggering its activity remained unexplained. Although the collision rates in the centaur region are expected to be very low, and impacts are thought not to be responsible for the mass-loss, since the recent indications that Chiron might possess a ring similar to Chariklo's, and assuming that there is debris orbiting around, the impact triggered mass-loss mechanism should not be excluded as a possible cause of its activity. From time series observations collected on Calar Alto Observatory in Spain between 2014 and 2016, we found that the photometric scatter in Chiron's data is larger than a control star's scatter, indicating a possible microactivity, possibly caused by debris falling back to Chiron's surface and lifting small clouds of material. We also present rotational light curves, and measurements of Chiron's absolute magnitudes, that are consistent with the models supporting the presumption that Chiron possesses rings. By co-adding the images acquired in 2015, we have detected a $ \sim $5 arcsec long tail, showing a surface brightness of 25.3 mag(V)/arcsec$^{2}$.