COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1951 Konkoly Observatory Budapest 1981 April 8 HU ISSN 0374-0676 FURTHER SPECTROSCOPIC OBSERVATIONS OF BD + 16d516 (V 471 TAURI) Spectroscopic observations of the white-dwarf eclipsing binary V 471 Tauri are reported. The star was observed in February 1980 and 22 spectra were obtained where, particularly H and K lines of CaII were investigated (Hamzaoglu, 1980). Further simultaneous spectroscopic and photoelectric observations were carried out, starting from November 1980 until the second part of February 1981. The spectroscopic observations were carried out at the Astrophysical observatory of Asiago-Italy and the photoelectric observations were achieved at Ege University Observatory-Izmir. In the course of spectroscopic observations over 70 spectra with the 122 cm telescope (cassegrain), prism spectrograph (with dispersions 42 A/mm and 40 A/mm at lambda3968 and lambda3933 A, respectively) and RCA image-tube were obtained. Some of these spectra were taken in a "single-trail" mode as suggested by Walker and Chincarini (1968). In this mode of observations the H and K double reversals (absorptions+emissions) of CaII are seen more clearly and any kind of variation, if exist can be discerned very easily. Also in the same spectra, apart from the central emission component (K_3) of lambda3968 line, the two weaker emissions (K_2r, red displaced and K_2v, violet shifted) within the same absorption line are clearly visible. The radial velocities of these K_2v, K_2r emissions were determined and presented in Fig. 1. The orbital elements of the star were determined using 36 spectra appropriately spaced in orbital phases. The spectral lines of K0V spectral type star were used in the determination of the mean radial velocity. From the radial velocity curves it was deduced that, a. All spectral lines utilized in the radial velocity measurements are in absorption (as seen in K0V spectral type stars) except lambda3933, lambda3968 (H,K) of CaII and very likely H_alpha is in emission (H_alpha was separately observed with the 182 cm telescope and Echelle spectrograph). [FIGURE 1] Fig.1. Displaced emission lines of the K0V component of the star. They were measured in the single-trail spectra among 0.69-0.87 orbital phases. Dots, open circles and dotted circles indicate; a. Central emission (K_3) b. Red-shifted emission (K_2r) and violet displaced emission (K_2v) of lambda3968 A line, relative to the baricentric gamma velocity (+39 km/s) of the star. The first four spectra (0.69-0.76 phases) were obtained (January 2, 1981) on the same night consecutively on the same plate. Whereas the last six spectra (0.77-0.87 phases) were obtained (December 31, 1980) in the same way (single-trail) as the first four spectra. b. Although lambda3933 and lambda3968 A emission lines of CaII are chromospheric in origin their radial velocities conform with the mean radial velocity curve. (Fig. 2.) [FIGURE 2] Fig.2. Observed data obtained from lambda3968 and lambda3933 A emission lines of CaII. The solid curve represents the orbital elements with e=0.0, K=147 km, gamma=39 km/s (V0) and P=0.52118286 (assumed). c. Although 4340 A (H_gamma) line (in absorption) appears clear and sharp in the spectra, does not conform with the radial velocity curve, obtained using the other lines within the spectra. H_gamma exhibits different baricentric gamma velocity values (Fig. 3). Acknowledgements: I would like to thank Prof. L. Rosino, Director of the Astrophysical Observatory of Asiago for constant comments on the spectra and to Prof. L. Bernacca for the financial support obtained through CNR. [FIGURE 3] Fig.3. H_gamma (lambda4340 A) data measured in the same spectra, do not conform with the radial velocity curve obtained for the elements cited in Fig.2. ESAT HAMZAOGLU Ege University Observatory P.K. 21 Izmir-Turkey References: Hamzaoglu, E., 1980 I.B.V.S. No. 1860 Hamzaoglu, E., 1980, Astrophys.Space Sci. to be published Walker, M.F. and Chincarini, G., 1968. Ap.J., 154, 157 [BIBCODE 1968ApJ...154..157W ]