Subleading power corrections for event shape variables in $e^+ e^-$ annihilation

We consider subleading power corrections to event shape variables in $$e^+e^-$$ collisions at the first order in the QCD coupling $$\alpha _{\textrm{S}}$$. We start from the jettiness variable $$\tau _2$$ and the $$y_{23}$$ resolution variable for the $$k_T$$ jet clustering algorithm and we analytically compute the corresponding cumulative cross section. We investigate the origin of the different power suppressed contributions in the two-jet limit and trace it back to their different coverage of the phase space. We extend our analysis to the case of thrust and of the C-parameter, and we finally discuss a class of observables that depend on a continuous parameter giving different weight to central and forward emissions and we evaluate the corresponding subleading power corrections.