Measurements of magnetic fields in young main-sequence stars

The Zeeman analyzer at the coude' spectrograph of the 224-cm (2.2-m) telescope on Mauna Kea has been used to search for magnetic fields in young main-sequence stars at a dispersion of 3.3 A mm . Eight stars of spectral types FO V-KO V were selected as young stars by one or more criteria: intense Ca ii emission cores, high Li content, high axial rotation. Four of the stars clearly show no detectable magnetic fields and a fifth one probably has no field. Ten spectrograms of y Vir N indicate that it does have a small, possibly variable magnetic field. There is marginal evidence in favor of weak magnetic fields in the two coolest stars, Boo A and 70 Oph, both of which show intense Ca ii emission. Subject headings: Ca ii emission - late-type stars - magnetic fields