SIMBAD references

High-dispersion, high-S/N photographic spectra of the eclipsing composite-spectrum binary HR 6902 have been obtained during and near two primary eclipses. From the spectra we isolate the phase-dependent chromospheric absorption lines, and present a list of identifications and measurements of 133 such features. We collate eclipse photometry from four different eclipses, and derive the geometry of the system by modelling the eclipse light curves. The orbital inclination is found to be 87deg. From the radii and the temperatures (the latter derived from applications of model atmospheres) we calculate the absolute magnitudes of the components. A significant mismatch between the colour indices of both components and their apparent spectral types indicates that the system is seen through about 0.6mag of interstellar absorption, which had not been appreciated in earlier studies. Measured chromospheric radial velocities show a spread suggestive of large-scale motions within the chromosphere.