A SEARCH FOR LAMBDA-BOOTIS STARS IN OB ASSOCIATIONS

A search for lambda Bootis stars in two OB associations, Orion OB1 and Lacerta OB1, has been carried out. One lambda Bootis star has been di scovered in the Orion OBI association. In addition, nine A-type stars which appear to be slightly metal weak have been found in the two asso ciations. The lambda Bootis star is situated on the Zero-Age Main Sequ ence (ZAMS). The discovery of these stars strengthens the hypothesis t hat the lambda Bootis stars are related to a short-lived evolutionary phase associated with the arrival of the star on the ZAMS.