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Abstract

Stripped envelope supernovae are a sub-class of core-collapse supernovae showing several stages of H/He shell stripping that determines the type: H-free/He-poor SNe are classified as Type Ic, H-poor/He-rich are Type Ib, and H/He-rich are Type IIb. Stripping H/He with only stellar wind requires significantly higher mass-loss rates than observed while binary-involved mass transfer may usually not strip enough to produce H/He free SNe. Type Ib/c SNe are sometimes found to include weak H/He transient lines as a product of a trace amount of H/He left over from stripping processes. The extent and mass of the H/He required to produce these lines is not well known. In this work, a 22 M_⊙ progenitor model is stripped of the H/He shells in five steps prior to collapse and then exploded at four explosion energies. Requiring both optical and near-infrared He i lines for helium identification does not allow much He mass to be hidden in SE–SNE. Increasing the mass of He above the CO core delays the visibility of O i 7774 in early spectra. Our SN Ib-like models are capable of reproducing the spectral evolution of a set of observed SNe with reasonable estimated E_k accuracy. Our SN IIb-like models can partially reproduce low energy observed SN IIb, but we find no observed comparison for the SN IIb-like models with high E_k.