COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1828 Konkoly Observatory Budapest 1980 August 11 HU ISSN 0374-0676 PERIODS AND PHOTOGRAPHIC MEAN LIGHT CURVES OF 17 LONG PERIOD VARIABLES IN A FIELD AROUND alpha = 17h, delta = - 70deg. This bulletin summarizes the results of an investigation of 17 long period variables situated in Apus, Ara, and Triangulum Australe. Six out of these stars were already known to be variable (CF Aps, EF TrA, FS TrA, CQ Aps, DN Aps, and XX Aps), but up to now no periods or mean light curves have been determined for these stars. The remaining eleven variables have been discovered with a blink microscope. The light variability of the present 17 long period variables has been measured on 401 photographic plates that were taken with the 10-inch telescope of the Boyden Observatory. The observations span 11 years. The apparent magnitudes of the variables were estimated with Pogson's method using at least six comparison stars for each variable star. When a variable becomes fainter the the limiting magnitude of the photographic plates, which is about 16.1mag., it is given the apparent magnitude 16m1. The apparent magnitudes of the comparison stars have been derived from stars counts on one square degree around each variable and from interpolations in the tables of the Groningen Publication Nr. 43. The periods and the mean light curves have been determined by means of computer analysis using the Phase Dispersion Minimization (PDM) method (Stellingwerf, 1978), which is extremely adequate for the determination of the periods and the mean light curves of long period variables. The PDM method has been used with a bin structure N_b = 20, N_c = 2. The variables are indicated on identification charts 1 - 17. These identification charts cover a field of about 30 minutes of arc square and have North on top. On Table 1 we have listed for each variable the program number, the provisional coordinates, the period, the apparent magnitude of maximum light of the mean photographic light curve, the number of observed moments of maximum light, and the epoch. No amplitude is given for stars that become fainter than the limiting amplitude of the photographic plates. Note that the maximum of the mean light curves underestimates the true maximum by an amount of about A/N_b = 0.2m which is about the accuracy of the magnitude determination of the comparison stars. On Table 2 we have summarized the basic quantities of the PDM analysis of the light curves. Theta_min is typically of the order of 0.1 or smaller so that generally 90% or more of the initial variance has been removed by the mean light curve at the indicated period. The signal to noise ratio is typically 4 to 5. We have also given a list of remarks on individual variables. In this list we have identified the six variables which were already known in the literature, and we have also indicated the stars that are invisible during a considerable fraction of the total phase intervals. Light curves are shown in Figures 1 - 17. Individual observations are indicated by an asterisk *, bin means by+, the spline fit to the bin means, which is used to remove the oscillation from the data and to calculate the residuals, by x; when two of or all three symbols coincide, the symbol Q is used. M. GOOSSENS and C. WAELKENS Astronomisch Instituut Katholieke Universiteit Leuven Naamsestraat 61 B-3000 LEUVEN Belgium Reference: Stellingwerf, R.J. : 1978, Ap. J. 224 953. [BIBCODE 1978ApJ...224..953S ] Table I JD a b Nr 1900 1900 P V_max A NE Nm 2438000+ 1 16h08m03s - 68d18.7 206.3 12.4 219 3 729 2 16 21 08 - 72 22.0 233.9 11.6 295 4 769 3 16 27 51 - 69 04.0 265.5 14.45 326 1 644 4 16 30 12 - 68 03.1 224.7 10.9 3.25 316 4 796 5 16 30 50 - 66 22.2 271.6 12.95 321 2 717 6 16 32 22 - 69 49.3 202.0 14.5 289 2 760 7 16 35 01 - 71 49.7 249.6 13.0 1.5 302 5 781 8 16 36 00 - 64 58.2 206.8 13.05 225 1 826 9 16 44 03 - 66 43.2 253.6 14.8 334 1 806 10 16 47 42 - 71 19.5 137.0 10.8 2.15 314 4 700 11 16 55 17 - 72 17.2 390.5 12.8 350 4 696 12 16 56 25 - 65 08.1 279.2 12.15 229 1 710 13 16 59 19 - 72 04.5 209.9 13.95 329 1 765 14 17 11 13 - 66 57.9 204.9 13.8 319 1 737 15 17 13 52 - 66 11.8 178.6 14.1 284 2 713 16 17 14 23 - 69 12.8 170.0 12.3 2.95 322 5 720 17 17 26 24 - 66 49.9 225.8 11.65 322 4 687 Nr : program number which refers to the identification chart; alpha delta: provisional coordinates for 1900; P : period in days; Vmax:apparent magnitude of maximum light of the mean photographic light curve; A : total variation of the mean photographic light curve; NE : number of estimates; Nm : number of observed moments of maximum light; JD : mean epoch. Table II Characteristic quantities of the PDM analysis of the light curves Nr sigma^2 {sigma_N}^2 {sigma_0}^2 Theta_min epsilon 1 1.523 0.042 1.481 0.035 5.9 2 1.807 0.193 1.614 0.118 2.9 3 0.132 0.005 0.127 0.064 5.0 4 1.279 0.053 1.226 0.053 4.8 5 1.206 0.063 1.143 0.074 4.3 6 0.439 0.008 0.431 0.022 7.4 7 0.314 0.003 0.311 0.100 3.3 8 1.438 0.048 1.390 0.043 5.4 9 0.250 0.009 0.241 0.052 5.1 10 0.426 0.025 0.401 0.069 4.0 11 1.475 0.025 1.450 0.024 7.6 12 1.781 0.051 1.730 0.038 5.9 13 0.577 0.040 0.537 0.091 3.6 14 0.696 0.031 0.665 0.059 4.6 15 0.437 0.039 0.398 0.106 3.2 16 1.121 0.047 1.074 0.062 4.8 17 2.926 0.072 2.854 0.033 6.3 Individual remarks Var.2.= CF Aps. Var.3.= Invisible during about 2/3 of the total phase interval.Var.4.= EF TrA. Var.5.= FS TrA. Invisible during about 1/2 of the total phase interval.Var.7.= CQ Aps. Var.9.= Invisible during about 7/10 of the total phase interval. Var.13.= DN Aps.Var.15.= Invisible during about 3/5 of the total phase interval.Var.16.= XX Aps.Semiregular variable, brightness at minimum light is variable. [FIGURE 1] FIG 1 Variable 1 [FIGURE 2] FIG 2 Variable 2 [FIGURE 3] FIG 3 Variable 3 [FIGURE 4] FIG 4 Variable 4 [FIGURE 5] FIG 5 Variable 5 [FIGURE 6] FIG 6 Variable 6 [FIGURE 7] FIG 7 Variable 7 [FIGURE 8] FIG 8 Variable 8 [FIGURE 9] FIG 9 Variable 9 [FIGURE 10] FIG 10 Variable 10 [FIGURE 11] FIG 11 Variable 11 [FIGURE 12] FIG 12 Variable 12 [FIGURE 13] FIG 13 Variable 13 [FIGURE 14] FIG 14 Variable 14 [FIGURE 15] FIG 15 Variable 15 [FIGURE 16] FIG 16 Variable 16 [FIGURE 17] FIG 17 Variable 17 [FIGURE 18] [FIGURE 19]