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Evolution of close binaries often proceeds through the common envelope stage.The physics of the envelope ejection (CEE) is not yet understood, and severalmechanisms were suggested to be involved. These could give rise to differenttimescales for the CEE mass-loss. In order to probe the CEE-timescales we studywide companions to post-CE binaries. Faster mass-loss timescales give rise tohigher disruption rates of wide binaries and result in larger averageseparations. We make use of data from Gaia DR2 to search for ultra-widecompanions (projected separations $10^3$-$2\times 10^5$ a.u. and $M_2 > 0.4$M$_\odot$) to several types of post-CEE systems, including sdBs, white-dwarfpost-common binaries, and cataclysmic variables. We find a (wide-orbit)multiplicity fraction of $1.4\pm 0.2$ per cent for sdBs to be compared with amultiplicity fraction of $5.0\pm 0.2$ per cent for late-B/A/F stars which arepossible sdB progenitors. The distribution of projected separations ofultra-wide pairs to main sequence stars and sdBs differs significantly and iscompatible with prompt mass loss (upper limit on common envelope ejectiontimescale of $10^2$ years). The smaller statistics of ultra-wide companions tocataclysmic variables and post-CEE binaries provide weaker constraints.Nevertheless, the survival rate of ultra-wide pairs to the cataclysmicvariables suggest much longer, $\sim10^4$ years timescales for the CEE in thesesystems, possibly suggesting non-dynamical CEE in this regime.

Inferred timescales for common envelope ejection using wide astrometric companions