Investigation of IUE spectra of the CP star ET And (HD 219749).

Abstract

Seventeen IUE spectra of ET And (HD 219749, HR 8861) have been investigated. The rotational velocity as derived by using the Fourier technique is v sin i = 78.8 + or - 9.0 km/sec, which is in good agreement with the values given in the literature. However, there is a large difference between v sin i measurements of photospheric lines and those of resonance lines. A circumstellar envelope would be a good explanation for this phenomenon. On grounds of periodic light variations of this star, a new method was developed to search for possible variations of continuum and spectral lines. This method of the so-called common line index is independent of the measurement of the continuum intensity, which is a great advantage in the case of the often heavily blended UV spectra. Periodic variations of continuum and spectral lines could have been detected.