Interstellar absorption in the Mg II resonance line k2 and h2 emissions

We have studied high-resolution (0.2 A) IUE spectra for the long wavelength range (1800<lambda<3000 A). We show that narrow interstellar Mg II lines are seen in the center of the k2 and h2 emissions from nearby stars with large rotational velocities. It is found that for all observed stars the radial velocity of the central k3 absorption component in the rest system of the star is strongly correlated with the mirror image of the radial velocity of the stars, showing that a major fraction if not all of the k3 absorption is due to interstellar absorption in the solar neighborhood. The violet to red asymmetry of the k2 emission also correlates with the radial velocities of the star, showing again that the shift of k3 is due to the velocity shift of the local interstellar cloud with respect to the star. This does not refer to the luminous cool stars, which also show intrinsic k3 component. For high-luminosity G and K stars additional absorption components are seen, called k4 by Stencel et al. which are probably circumstellar. For these stars the mass-loss analysis remains valid. The dividing line between stars with and without loss is even more evident