Observations of the long-lasting activity of the distant Comets 29P Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR) and C/2002 VQ94 (LINEAR)

TL;DR

This study observes three distant comets at large heliocentric distances, measuring dust production and mass loss to understand their long-lasting activity and surface sublimation processes.

Contribution

It provides new observational data on dust production and surface sublimation for three comets at large distances, highlighting the ongoing activity of these objects.

Findings

Comets exhibit sustained activity at 5.5 to 7.08 AU from the Sun.

Dust production rates vary with model assumptions.

Surface layer depletion is necessary to explain observed activity.

Abstract

We investigated three comets, which are active at large heliocentric distances, using observations obtained at the 6-m BTA telescope (SAO RAS, Russia) in the photometric mode of the focal reducer SCORPIO. The three comets, 29P/Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR), and C/2002 VQ94 (LINEAR), were observed after their perihelion passages at heliocentric distances between 5.5 and 7.08 AU. The dust production rates in terms of Afrho was measured for these comets. Using the retrieved values, an average dust production rate was derived under different model assumptions. A tentative calculation of the total mass loss of the comet nucleus within a certain observation period was executed. We calculated the corresponding thickness of the depleted uppermost layer where high-volatile ices completely sublimated. The results obtained in our study strongly support the idea that the observed activity of Comet SW1 requires a permanent demolition of the upper surface layers.