Variability of the iron K emission line in the Seyfert 1 galaxy NGC 3516

We present strong evidence for variability of the flux of the iron K alpha emission line in the Seyfert 1 galaxy NGC 3516. Two ASCA observations, separated by similar to 1 yr, show a marked decrease in continuum flux by similar to 60 per cent. The flux in the broad iron K alpha line decreased by the same factor in this time period, with no evidence for changes in the line profile. The line variability is significant at > 99 per cent confidence, and rules out models in which the line is produced in a molecular torus located at > 1 pc from the nucleus. An accretion disc is considerably more likely.