A separation in the gas tail of a comet, resulting from changes in the strength and direction of the local interplanetary magnetic field (IMF) carried by the solar wind. The existing gas tail separates from the coma and is swept away downwind, to be replaced by a new tail which develops in a slightly different direction governed by the prevailing IMF. The new gas tail can, in turn, be subject to disconnection. Several such events were recorded in the tail of Halley's Comet at its 1910 return, which coincided with a period of high solar activity.
Subjects: Astronomy and Astrophysics.