The Rotation Period of Comet 29P/Schwassmann-Wachmann 1 Determined from the Dust Structures (Jets) in the Coma

TL;DR

This study determines the rotation period of comet 29P/Schwassmann-Wachmann 1 using dust jet structures observed in the coma, revealing a rotation period of approximately 12 days despite activity beyond water ice sublimation zones.

Contribution

The paper introduces a novel method of estimating the comet's rotation period through analysis of dust jets in CCD images, providing new measurements for this active comet.

Findings

Rotation period estimated at ~12 days

Active dust jets observed beyond water ice sublimation zone

Method demonstrates effectiveness for active comets

Abstract

The results of the photometric observations of comet 29P/Schwassmann-Wachmann 1 are analyzed. The comet demonstrates substantial activity at heliocentric distances larger than 5 AU, outside the water ice sublimation zone. The CCD images of the comet were obtained in wideband R filters at the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) and at the 2m telescope of the Peak Terskol Observatory. The processing of the images with special digital filters allowed the active structures (jets) to be distinguished in the dust coma of the comet. With the cross correlation method, the rotation period of the cometary nucleus was determined as 12.1 and 11.7 days for the observations taken in December 2008, and February 2009, respectively. The probable causes of the difference in the estimates of the rotation period of the cometary nucleus obtained by differen authors are discussed.