MGII H and K line observations of del SCT variables.

Abstract

IUE observations of seven Delta Scuti variables and a comparison star are reported with a comparison of the Mg II h and k lines to those of previously observed normal stars. Evident chromospheric emission is observed in three Delta Scuti variables: tau Cyg, beta Cas and rho Pup. Possible emissions are suggested for omega-1 Eri (F2III), iota Cyg, tau Peg, and kappa-2 Boo. Values of the observed emission widths fit well in diagrams of emission width-absolute magnitude, which, if correct, confirms the suggestion by Kondo et al. (1977) of possible evidence of chromospheric emissions in late A stars. A possible relation between emission widths and periods of pulsation is also discussed.