Mass loss rates for northern OB-stars

A mass loss survey of 44 O- and early B-type stars in northern OB associations is presented. For 22 stars mass loss rates were derived from Hα equivalent widths using the method of Klein and Castor (1978). For 15 stars uper limits of the mass loss rates were estimated. For the remaining 7 stars Hα and Hβ equivalent width values are given but no quantitative evaluation of M was possible. The results are compared with present ideas concerning the relation between mass loss and other basic stellar parameters