Magnetic field of chemically peculiar stars in Orion OB1 association

Abstract

We present results of magnetic field measurements for 57 chemically peculiar stars in the Orion OB1 association. We havefound 32 magnetic stars in the association (or 56% of CP stars) which is more than twice larger than usual 25% for coolerAp stars. We have found that the proportion of chemically peculiar stars relative to the normal ones strongly decreaseswith age in the interval from 2 Myr to 10 Myr. The proportion of magnetic stars relative to all peculiar stars also stronglydecreases (more than twice) with age in the same time interval as well as the magnetic field strength.