A proper motion membership analysis of the Orion Nebula region.

An analysis of 1058 stars in the extensive proper motion study of the Orion Nebula region by Parenago (1954) has resulted in the identification of over 550 stars with a membership probability greater than 50 percent. This more than triples the number of previously known members of this region. The area covered by this study is nine times that studied by McNamara (1976) and includes a large area relatively unaffected by nebula emission. Comparisons of the proper motion membership assignments made in this paper with other independent criteria are in excellent agreement.