COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3665 Konkoly Observatory Budapest 25 September 1991 HU ISSN 0374 - 0676 The optical behaviour of the old nova RR Pictoris in 1985/86 We present spectroscopic and photometric observations of the old nova RR Pic obtained in Febr. 1985 and March 1986 at the ESO Observatory La Silla/Chile. Spectroscopy was performed at the 1.5 m telescope equipped with the Boller & Chivens spectrograph and the IDS whereas the 50 cm telescope with the standard single-channel photometer was used for UBVRI photometry. In total 55 spectra and 923 UBVRI measurements were collected. Tables 1 and 2 give details of the observations. The spectra cover the wavelength region lambda lambda 4500 - 6900 A (114 A/mm) and lambda lambda 3700 - 7200 A (172 A/mm) and have a resolution of about 7 A and 10 A respectively. The most pronounced features are the emission lines of HeII lambda 4686 A and H alpha. Radial velocities of these lines were determined and folded with the photometric period given by Vogt (1975). Fig. 1 shows the resulting radial velocity curve for the HeII line which indicates K~=120 km/s and gamma~=30km/s. Similar values were also derived from the H alpha measurements. Wyckoff and Wehinger (1977) found the same amplitude and phasing but a different systemic velocity (+40 km/s) from their HeII radial velocity curve. Both lines show a variable asymmetry through the orbital cycle: H alpha even exhibits a double-peaked structure with a tendency for the blue component to be stronger than the red one around phase 0.1 - 0.2 and vice versa around phase 0.7 (Fig. 2). Onset and duration of this behaviour is, however, not strictly the same for each orbital cycle. The equivalent widths of both lines show a pronounced maximum near phase 0.5 - 0.6 and are then stronger by about a factor of 1.5 than around phase zero. Warner (1986) noticed a disappearance of the strong double-humped shape of the light curve of RR Pic during the years 1972 - 1984 which seemed to be gradually replaced by the second of two minima as the dominant recurrent feature. Haefner and Metz (HM, 1982) recognized these minima as stable features in their light curves obtained in 1980. To elucidate the general behaviour of the present photometric data we examined average light curves covering several orbital cycles. A periodogram analysis revealed no change of Vogt's (1975) period of 0.1450255d. Therefore, the measurements of 1985 and 1986 were superimposed according to his elements respectively. Fig. 3 presents a few of the resulting light curves. The characteristic 'W'-shape (HM) is still present though less pronounced in the 1986 data. The first minimum gradually disappears for longer wavelengths due to the growing extent of the principal maximum. The position of this minimum appears now to be shifted from phase ~0.43 (1980) to phase ~0.52 whereas the second minimum is still at the same position. Table 1. Spectroscopy of RR Pic Date Start (UT) Duration Integr. No. of Disp. Time(m) spect. (A/mm) 26 Feb 1985 0h40m 5h31m 16 17 114 27 Feb 1985 0h31m 5h31m 16 18 114 28 Feb 1985 4h52m 1h22m 12 6 172 13 Mar 1986 1h04m 4h35m 16 14 114 Table 2. Photometry of RR Pic Date Start (UT) Duration No. of UBVRI sets 18 Feb 1985 1h57m 4h41m 63 19 Feb 1985 1h16m 5h21m 77 21 Feb 1985 1h07m 5h16m 90 22 Feb 1985 1h02m 5h31m 103 24 Feb 1985 1h05m 5h13m 98 25 Feb 1985 0h59m 5h31m 109 13 Mar 1986 2h01m 3h17m 76 15 Mar 1986 0h27m 4h49m 115 17 Mar 1986 0h51m 4h09m 99 20 Mar 1986 0h39m 4h05m 93 [FIGURE 1] Fig.1 Radial velocity curve of RR Pic based on the HeII lambda4686 line. Phases are computed using Vogt's (1975) elements. Upper left: Estimated error of a single measurement. [FIGURE 2] Fig.2 Profile changes of Halpha for the run of Febr. 26, 1985. Phases are indicated on the right. [FIGURE 3] Fig.3 Average light curves (1985) of RR Pic (75 bins per period). The position of the first (1) and second (2) minimum according to HM are indicated. For further explanation see text. Our new measurements confirm the phase relation between radial velocity curve and light curve given by HM which led to an unusual interpretation with respect to the energy distribution within the accretion disc of RR Pic. Since the system is barely detectable in the infrared (Feast and Glass, 1974) the wavelength dependent changes in the light curve can hardly be ascribed to the influence of the secondary. This behaviour as well as the shift of the first minimum is rather due to the energy distribution in the disc and its gradual variation. At the same time the overall brightness has remained at an almost constant value around V ~= 12.25 since ~1980. R. HAEFNER W. BETZENBICHLER Universitats-Sternwarte Scheinerstrasse 1 8000 Munchen 80 Germany REFERENCES: Feast, M.W., Glass, I.S.: 1974, Mon.Not.R.astr.S. 167, 81 [BIBCODE 1974MNRAS.167...81F ] Haefner, R., Metz, K.: 1982, Astron.Astrophys. 109, 171 [BIBCODE 1982A&A...109..171H ] Vogt, N.: 1975, Astron.Astrophys. 41, 15 [BIBCODE 1975A&A....41...15V ] Warner, B.: 1986, Mon.Not.R.astr.S. 219, 751 [BIBCODE 1986MNRAS.219..751W ] Wyckoff, S., Wehinger, P.A.: 1977, IAU Coll. No. 42, p. 81 [BIBCODE 1977ivsw.conf..201W ]