COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2600 Konkoly Observatory Budapest 10 October 1984 HU ISSN 0374-0676 LONG PERIOD VARIABLE CARBON STARS AT GALACTIC LONGITUDE 86deg. To search for light variations and study variability of carbon stars the 80 cm Schmidt telescope at the Baldone station of the Radioastrophysical Observatory was used for monitoring all known accessible C-stars situated in five-degree wide zone stretched perpendicular to the galactic equator between latitudes +9.5d and -9.5d and centered at longitude 86d. In each of the five partly overlapping fields of 5d-diameter 50 - 75 red plates, 13 - 32 visual films and 20 - 23 blue plates were taken. The observations span 11 years from 1972 to 1983. Because of the largest number of observations the red (m(R)) magnitudes, best of all, indicate the existence of light variations and display their properties. Preliminary results for some of the stars were given earlier (Alksne et al., 1983). Characteristics of variations observed in red light for long period variable stars are summarised in Table I. The name for known or suspected variables or the (four-digit) number according to Stephenson (1973) or the number according to the catalogue of Baldone carbon (BC) stars (Alksne et al, 1980, 1983; Alksnis and Ozolina, 1983; Star catalogue and files available at the stellar data centre, 1982), the epoch of the maximum brightness (M0), the period in days (P), the m(R)-magnitude at maximum (m(R) max) and minimum (m(R) min) light of the mean light curve and the total range (Delta m(R)) of m(R)-variations are given. Additional information for several stars follows. V Cyg. After J.D. 2444150 m(R) max = 6.9m, m(R) min = 8.8m and the shape of the mean light curve differs from the earlier observed one, in addition, secondary oscillations with P2 approx.= 2P and m(R)-range of 1.2m seem to start. BC 48. Very large range (2.0m) secondary variations with maxima at J.D. 2 442 050 and 2 443 550. U Cyg. Slow secondary variations, m(R)-range 0.5m, time scale about 6P. V 1426 Cyg = CIT 13 = IRC+40 485 = AFGL 2781. 2946. Stable light curve, bump at phase 0.7. Table I Star M0 J.D. P m(R) max m(R) min Delta m(R) 244... V Cyg 1091* 421d43* 7m90 9m80 3m7 BC48 2050 496 11.44 12.94 3.0 U Cyg 2246 462.4* 6.08 8.44 2.9 V1426 Cyg 1420 482 9.24 11.04 2.5 2946 1917 424 11.34 13.02 2.0 BC245 2000 350 12.2 13.3 2.0 BC236 1775 401 13.20 14.16 1.9 BC244 1940 356 11.2 13.1 1.9 V1555 Cyg 1559 518 12.39 13.89 1.9 BC240 1924 457 13.38 14.28 1.6 V1554 Cyg 1690 330 11.4 12.6 1.4 BC40 2250 345 10.40 11.23 1.1 BC242 1847 405 12.24 13.40 1.1 BC243 2675 361 12.3 13.0 0.8 BC41 3305 381 10.5 10.9 0.7 NSV 12973 2250 413 8.60 9.00 0.6 V1541 Cyg 1550 370 10.16 10.50 0.4 * from Kukarkin et al.,1976, III Suppl. to the III Edition of the General Catalogue of Variable Stars. BC 245. Secondary variations with m(R)-range 1.6m and large changes of amplitude in different cycles. BC 236. Variations of the light curve from cycle to cycle and gradual brightening of the star by about 0.5m during the observing interval. BC 244. Stable light curve, steep ascending branch (M-m = 0.35) not typical for carbon long period variables as observed also for MQ Cyg. V1555 Cyg. Secondary variations with m(R)-range 1.4m and possible cycle length 4 - 5 P. BC 240. Large dispersion observed in ascending branch of the mean light curve. V 1554 Cyg. Rather stable light curve. BC 40. Small (0.4m) secondary variations with time scale about 5 -6 P. BC 242. Small change of the shape of the mean light curve after J.D. 2 443 900. NSV 12973. Very slow gradual fading by about 0.3m during our observing interval. For the 39 carbon stars not included in Table I the m(R)-ranges are 0.3m - 0.9m and light variations less regular or irregular. The rest seven of the measured carbon stars seem to be non-variable judging from dispersion of their m(R) and m(V) values. A. ALKSNIS and Z. ALKSNE Radioastrophysical Observatory Latvian Academy of Sciences, Riga Latvia, U.S.S.R. References: Alksne, Z., Alksnis, A., Eglitis, I. 1980, Investigations of Sun and Red Stars, 13, 5. Russian. [BIBCODE 1981ISKZ...13....5A ] Alksne, Z., Alksnis, A., Eglitis, I. 1983, Nauchnye Informacii, Riga, Zinatne, 52, 138. Russian. [BIBCODE 1983NInfo..52..138A ] Alksnis, A., Ozolina, V. 1983, Investigations of Sun and Red Stars, 19, 40. Russian. [BIBCODE 1983ISKZ...19...40A ] Star catalogs and files available at the stellar data center, 1982, Bull. Inform. Centre de Donnees Stellaires, No. 23, 108. Stephenson, C.B. 1973, Publ. Warner and Swasey Obs., 1, No. 4. [BIBCODE 1973gcss.book.....S ]