SIMBAD references

We discuss a new approach to the problem of the origin of λ Boo stars. It is proposed that at least some of these stars may arise from contact binary systems of W UMa type. Simple estimations based on this supposition can account for the present-day number of λ Boo stars in the solar neighbourhood, their masses and spectral classes. It is also important that the proposed scenario does not exclude circumstellar shell formation, which is responsible for the chemical peculiarities of λ Boo stars.