High-Dispersion Spectrograms of T Coronae Borealis.

Abstract

Velocities from absorption lines.-Coudé spectrograms of T C,rB, when it is fainter than 9 mag., show an absorption-line spectrum of class gM3, associated with nova-like emission lines, just as before the February, 1946, outburst. The variable velocities from the gM3 source are represented by a sine-curve with a semi-amplitude of 21 km/sec, a period of 230.5 days, and a systemic velocity of -29 km/sec (see Fig. 1). Velocities from bright lines.-The emission lines associated with the nova source also give a systemic velocity of -29 km/sec but show no certain velocity variation. Neither orbital motion nor pulsation seems adequate to explain a velocity variation for the gM3 source and a lack of variation in the velocities from the emission-line source; but no other explanation is at hand. Structure of the bright lines-Curves, photometric tracings, and reproductions of the spectrograms serve to illustrate a variety of structural changes in the bright lines. Intensities of the bright lines in relation to the light-curve are summarized in Table 5 and Fig. 7