COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 879 Konkoly Observatory Budapest 1974 March 30 FLARES OF UV CETI, 1970 Continuous U-band photoelectric photometry of UV Ceti was obtained between October 27th and November 3rd, 1970, with the 60 cm reflector of the Cerro Tololo Interamerican Observatory. In 29.06 hours of monitoring a total of 233 events were recorded against a detection limit (Kunkel 1973) equal to or better than U_lim 17.0. The procedure for processing the data are identical to those used on earlier occasions (Kunkel 1968, 1970a, 1970b, 1973). The phenomena identified on the chart records are listed in Table 2. The table heading gives some pertinent stellar data, as well as the monitoring intervals with no interruptions exceeding a duration of one minute. In the main body of the table are given the date (column 1) and U.T. (column 2) of each event, as well as the air-mass (column 3), the U-magnitude at peak light, referred to comparison stars (column 4), the durations T_q at fractions q of peak light (columns 5 - 8), and the logarithms of the decay rate in magnitudes per minute, measured at one and at three magnitudes below peak light (columns 9, 10). Uncertainties greater than 10 percent or 0.1 magnitudes are denoted with the letter U following an entry. The letter C is used to denote complex events of possibly multiple peaks or other difficulty, for which the measured parameter could not be determined with the normally anticipated confidence. The data are judged to be at least 95 percent complete in a region bounded by the detection limit (Kunkel 1973) U_det 15.7 and T_0.5>0.03 minutes. The 178 events lying within this region have been used to determine the event rate coefficients in R (U) = exp [a (U-U_0)] events hr^-1 a = 1.14 +/- 0.09 U_0 = 14.11 +/- 0.08 Compared with results of earlier epochs we find no compelling evidence for change in the level of activity, thus confirming a result of Oskanian and Terebizh (1971). A rise in the activity of UV Ceti reported earlier (Kunkel 1973) appears to be at most part of fluctuation generally present in flare activity. At present the data are still too sparse to exclude cyclic activity or a slow trend, however. WILLIAM E. KUNKEL NELSON ZARATE Cerro Tololo Universidad de Chile Interamerican Observatory References: Kunkel, W.E. 1968, I.B.V.S., No. 315. 1970a, I.B.V.S., No. 442. 1970b, I.B.V.S., No. 462. 1973, Ap. J. Suppl., 25, 1. [BIBCODE 1973ApJS...25....1K ] Oskanian, V.S. and Terebizh, V. Yu. 1971, Astrofizika 7, 83. [BIBCODE 1971Afz.....7...83O ] MONITORING TIMES (U.T.) DATE INTERVALS 70 10 27 02 38.1 - 04 02.7 04 29.2 - 05 14.5 06 04.8 - 05 03.0 70 10 28 01 58.8 - 08 04.5 . - . . - . 70 10 29 00 51.8 - 07 55.6 . - . . - . 70 10 30 02 55.3 - 06 51.0 . - . . - . 70 11 01 06 47.3 - 07 45.0 . - . . - . 70 11 02 02 43.9 - 06 45.7 . - . . - . 70 11 03 04 46.6 - 07 37.3 . - . . - . TOTAL SAMPLE DURATION (HRS) 29.06 FLARES OBSERVED DATE U.T. AIRMASS U DURATIONS DECAY RATE (PEAK) T(.5) T(.2) T(.1) T(.05) J=3 J=3 (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) 70 10 27 02 38.07 1.076 15.20 0.05 C 0.160 02 48.24 1.070 15.91 0.3 U 02 54.13 1.062 16.16 0.65 C 02 59.70 1.057 14.51 0.56 3.2 4.8 0.29 03 15.52 1.044 13.74 0.06 0.13 0.8 1.11 -.70 03 24.68 1.035 15.68 0.27 03 28.01 1.033 15.78 0.45 03 30.94 1.031 15.190 0.17 03 33.36 1.030 15.450 0.7 2.0 03 38.83 1.027 15.780 4 03 51.85 1.024 14.96 0.7 3.0 0.1 04 02.40 1.022 14.26 0.17 0.33 0.65 3. U 1.22 04 22.93 1.025 15.39 0.03 0.14U 04 31.61 1.029 14.13 0.09 0.2 0.42 0.8U 1.56 04 36.56 1.031 15.48 0.25 05 03.44 1.052 14.82 0.40 1.2 U 05 04.37 1.054 14.27 0.20 0.35 0.5 U 0.65 06 49.34 1.297 15.46 0.17 07 04.22 1.360 15.13 0.04 0.4 U 07 25.10 1.410 14.27 0.06 0.13 1.06 07 38.27 1.555 13.70 0.13 0.27 0.5 2.4 1.35 07 50.03 1.654 13.04 0.24 0.75 1.9 3.3 0.40 -.030 70 10 28 02 05.62 1.138 14.740 0.13 0.9 2.6 U 02 20.30 1.108 14.39 0.05 0.59 2.2 3.3 02 27.00 1.100 16.62 1.0 02 28.54 1.094 15.17 0.2 0.7 2.2 02 52.63 1.061 15.82 1.7 3.6 03 02.19 1.050 15.54 0.7 2.8 03 06.31 1.046 15.84 0.23 1.0 03 12.96 1.040 16.25 0.2 03 17.26 1.037 14.85 0.04 0.35 1.1 03 25.91 1.031 13.53 0.7 0.18 0.6 U 1.5 1.49 -.34 03 38.33 1.026 15.27 0.07 0.2 0.7 U 03 52.92 1.023 14.54 0.15 0.73 1.3 U 0.63 03 55.74 1.023 14.92 0.07 0.1 U 03 57.38 1.022 15.36 0.10 0.7 U 03 59.59 1.022 14.83 0.24 04 07.04 1.023 15.62 0.14 04 20.93 1.026 16.26 1.2 04 34.71 1.032 15.55 0.13 05 02.07 1.055 12.89 0.13 0.37 0.52 1.7 0.57 -.110 05 07.64 1.061 14.15 0.05 05 28.14 1.089 15.87 0.35 05 41.60 1.119 13.54 0.06 0.25 0.78 1.75 1.49 06 02.26 1.157 13.54 0.28 0.47 0.60 0.87 0.57 0.36U 06 13.19 1.185 15.95 9.2 06 26.04 1.224 15.75U 0.24U 07 05.55 1.389 13.38 0.26 2.15 2.70 3.860 0.85 07 21.43 1.471 15.25 0.27 0.47U 07 29.60 1.521 15.61 0.12U 07 50.64 1.679 14.81 0.15 0.500 07 57.65 1.741 14.87 0.130 07 59.38 1.760 13.85 0.18U 0.88U 1.92U 0.3 08 02.77 1.790 14.78 0.07U 0.20U 70 10 29 01 23.20 1.247 14.82 0.20 0.70U 0.34U 01 28.09 1.230 15.60 0.20U 0.30U 01 32.44 1.217 15.50 0.28U 0.50U 01 36.98 1.205 15.45 0.30U 0.70U 0.39 01 49.74 1.167 15.34 0.11U 0.31U 01 52.20 1.159 15.21 6.060 0.26U 01 57.77 1.147 14.33 0.06 0.15U 0.61 02 12.23 1.115 14.12 0.10 0.42U 1.05U 0.85 02 26.93 1.091 15.68 0.07U 02 31.81 1.083 15.53 0.15U 02 44.29 1.066 15.20 0.09 0.40U 0.90U 02 54.47 1.054 15.64C 0.09C 02 59.42 1.049 14.44 0.11 0.35 0.50U 0.70 U 0.63U 0.71U 03 09.32 1.039 16.16 .64 .96 1.1U 03 24.10 1.031 15.96 0.10 0.11U 1.29 03 28.40 1.029 15.74 0.07 0.16U 0.26U 03 31.23 1.028 14.72 .06 .42 .80 60 03 32.62 1.027 14.71C 0.18C 0.48U 0.77U 03 34.84 1.026 15.77 .14U .15U 03 35.74 1.026 15.42 .18 .60 .29 03 49.00 1.027 16.90U 4 U 03 50.42 1.027 15.42 0.200 0.44U .52 04 26.32 1.030 13.64 0.12 0.19 0.30 0.48U 0.27 04 35.43 1.036 15.96 .20U .42U 04 37.81 1.037 16.18 .30 .55U 04 41.45 1.040 15.65 .07 .12U .16U 5.6U 04 44.26 1.042 14.33 0.04 0.16U 0.38U 0.49 04 45.63 1.043 16.08 .08U .35U .55U .71U 04 53.34 1.050 14.42 .11 .64U 1.20 1.54 .92U 05 00.14 1.058 15.70 0.15 0.15U 0.46U 05 03.57 1.061 15.42 .21 .52 .76U 0.57U 05 12.15 1.071 15.31 0.12 0.37U 0.49U 0.50 05 28.86 1.097 15.20 0.11 .30U .43U .79 05 34.16 1.106 15.56 0.16U 05 35.14 1.168 14.23 0.10 0.22 0.25U 0.270 0.94 05 37.53 1.113 15.42 .23U .33U 05 39.01 1.115 14.64 0.08U 0.23U 0.50U 0.84U 05 39.83 1.117 13.32 0.03 0.09 0.20U 0.36 1.71 0.65U 05 55.57 1.154 12.12 0.40 1.20 0.21 06 04.39 1.174 13.10 0.80 2.59U 0.42 06 18.11 1.214 14.55 0.10U .38C 1.37 06 18.52 1.214 14.87 .56 1.74 .09 06 26.23 1.237 16.00 .20 .30U .94U 06 39.25 1.283 15.57U .12 .26U 06 44.55 1.307 16.16 .16U .36U 06 50.79 1.333 15.01 0.1U 0.16 1.85U 07 14.15 1.454 15.12U .28U .66U 07 27.93 1.535 14.59 0.02 0.05 0.07 2.04U 07 30.61 1.555 14.46 0.04C 0.30C 0.55C 07 32.57 1.569 15.27 .25 .57U 0.45U 07 37.78 1.606 15.75 0.07U 07 36.85 1.614 15.74 0.06U 0.18U 0.04 07 43.55 1.654 15.07U .40C 07 48.70 1.696 15.01 0.11 0.25U 0.25U 0.11 70 10 30 03 00.53 1.044 15.36 0.08 0.13U 03 05.59 1.040 15.47 .14 .30U .46U .79U 03 07.82 1.038 13.79 0.16 0.47U 1.04U 1.56U 1.26 03 13.18 1.035 15.91 .10U .26U 03 15.24 1.034 15.36 0.05 0.1 3.56 03 32.54 1.025 15.23U .20 .70U 03 42.65 1.023 15.19 .27U .56U .55 03 46.10 1.023 13.65 0.06 0.26U 0.26U 0.75U 1.53 03 48.10 1.023 14.74 .41 1.07 1.48U .27 03 51.32 1.022 14.54 .30 1.44U 2.05U 03 54.10 1.022 15.04 0.27 0.9 U 04 01.06 1.023 15.12 .10 .32U 0.47U 0.66 04 05.59 1.024 15.46 .13U .25U 04 28.48 1.034 15.14 0.18 0.4 U 0.69 04 38.71 1.041 10.62 0.66 2.00U 0.18 04 47.71 1.049 13.51 2.11 0.38 04 52.94 1.054 14.74 .06 .17 04 55.38 1.057 15.00 .11 .18U 05 10.80 1.074 15.82 0.120 05 16.86 1.083 15.19 0.07U 0.15U 05 20.44 1.090 15.08 0.75 1.43U 0.18U 05 27.51 1.102 14.89 0.06 0.28U 05 29.17 1.104 14.72 .80 2.5 U 0.15 05 41.15 1.127 14.88 0.04 0.07U 05 41.90 1.129 14.90 .20 .52 .70 .83U 0.69 05 47.11 1.140 15.24 0.06 0.16 0.04 05 48.65 1.145 14.80 0.04 0.06 1.62 05 50.69 1.149 14.93 .23 0.6 0.78U 0.88U 3.35 05 54.11 1.157 15.21 .07 .17U 05 57.42 1.167 14.71 0.12 0.53U 0.8 U 0.5 05 59.85 1.172 13.06 .08U .16U 06 02.31 1.179 15.43 0.1 0.15U 06 10.15 1.202 15.22 .34 .86U 0.25 06 12.68 1.208 15.36C .65U .60U 06 13.08 1.244 15.30 .04 .08U 06 16.49 1.220 15.50 .08 .10 .12 1.79 06 21.27 1.223 15.65 .24 .32 .33U 1.01 06 34.79 1.283 15.34 .23U .74U 1.05U 06 47.64 1.337 15.59 .23U .37U 0.39U 0.64 70 11 1 06 49.32 1.384 15.39 .10 .23U 06 59.58 1.436 15.46 .06 .15U 1.86 07 03.61 1.459 15.52 .08U .18U 07 04.80 1.465 15.49 .11U .24U 07 07.83 1.483 15.33 .08U .18U 1.06 07 19.34 1.562 16.09 .08U .16U 07 21.12 1.576 15.20 0.05 0.13U 0.22U 1.1 07 24.13 1.595 14.85 0.03 0.04 0.05U 1.53 07 25.09 1.606 15.38 0.22 0.42 0.54U 0.53 07 27.58 1.621 15.71 .09U .26 .34U 07 39.59 1.722 14.71 0.05 0.18U 0.29U 0.92 70 11 2 02 48.68 1.045 16.18 0.12 0.14U 02 51.78 1.042 15.66 0.03 0.1 U 03 04.02 1.034 15.83 0.07 0.12 0.13 03 16.06 1.027 15.46 .06 .19U 03 17.58 1.027 15.66 0.07 0.1 0.14U 03 23.14 1.025 16.02 .14 .34 03 39.09 1.022 16.02 .05U .17U 1.26 03 40.39 1.022 13.62 0.11 0.27 0.47 0.67 1.15 0.58U 03 41.76 1.022 15.52 0.05 0.13 03 48.43 1.023 13.26 0.31 0.45 0.7 1.00 0.72 0.43 03 54.91 1.024 15.92 0.07 0.19U 03 55.99 1.025 14.03 .32 1.16 1.67 2.02 0.79 0.26 04 00.67 1.026 14.18 0.13 0.40 0.80U 1.04U 0.82 04 02.74 1.026 16.40 .60 .80U 04 09.43 1.029 15.52 .10 .16U .26 1.26 04 12.97 1.031 13.96 0.11 0.33 0.70U 1.04U 0.64 0.36U 04 22.92 1.038 16.18 .15 .21U 04 30.12 1.043 14.81 0.04 0.11 0.2 1.63 04 37.70 1.049 15.10 0.05 0.38 1.04 04 49.68 1.062 15.80 0.08 0.18U 05 04.68 1.084 16.06 .16 .24 0.27U 1.9 05 12.12 1.095 16.03 0.12 0.24 05 16.22 1.102 15.82 .16 .25 0.29U 05 18.34 1.106 15.82 .07 .13 05 28.00 1.125 15.88 0.03 0.07 0.11 05 36.77 1.143 15.86 0.16U 0.3 U 1.06 05 40.28 1.152 14.75 .20 .75 1.00 1.16 0.42U 05 44.26 1.161 15.84 0.13U 0.35U 05 42.42 1.169 14.55 .20 .30 0.33U 0.350 1.90 05 47.27 1.169 15.59 0.06 0.06 05 51.07 1.180 15.75 0.15U 0.450 0.8 05 55.61 1.194 15.48 0.06 0.15U 05 56.90 1.196 15.64 .09 0.13U 0.14U 1.66 05 59.47 1.208 15.31 0.24 0.35U 0.66U 0.76 06 04.93 1.227 14.72 0.15 0.28 06 08.01 1.237 15.52 0.1 U 0.16U 06 08.82 1.240 14.40 0.06 0.13 0.16 1.42 06 11.44 1.247 14.52 .25 .82 1.17U 1.360 0.1 06 12.72 1.250 15.64 0.15 0.26 06 13.45 1.254 15.52 0.10 0.2 06 25.61 1.295 15.57 1.72 2.00 06 29.18 1.307 15.41 .16 .38U 1.15 06 32.86 1.324 15.36 .14 0.3 0.42 0.92 06 34.82 1.332 15.14 0.11 0.16 1.59 70 11 3 04 47.83 1.066 12.50 0.11 0.28 0.35 0.38 1.15 1.18 04 55.66 1.077 15.97 .07 0.14 05 02.25 1.086 15.73 .44 .80U 05 06.86 1.094 15.65 .24 .40U .46U 05 09.34 1.097 15.87 .20U 0.30 05 28.44 1.136 16.18 .14 .30U 05 37.52 1.157 15.64 0.17 0.47 0.62U 05 39.73 1.161 13.52 0.14 0.53 1.43 2. 1.40 05 45.78 1.177 15.99 .29 .40U 05 54.15 1.199 12.36U 0.37U 1.62U 06 00.34 1.220 15.85 .10 .28 06 06.83 1.240 14.76 0.1 0.3 0.45 0.8 06 10.37 1.250 15.64 0.05 0.1 0.11U 06 13.53 1.261 16.41 .84 1.04U 06 13.91 1.310 12.59 .13U 06 26.06 1.311 12.83 0.24 0.4 U 0.71 06 38.23 1.360 15.31 0.06 0.08 06 42.62 1.379 15.63 0.04 0.08 06 47.65 1.415 14.40 0.02 0.08U 0.15U 06 51.49 1.431 14.71 0.05 0.11 1.12 06 51.67 1.431 15.76 0.16 0.17 06 52.00 1.436 15.11 0.1 0.12 07 03.86 1.508 15.42 0.12 0.23 07 04.31 1.515 14.87 0.20 0.33 07 10.12 1.548 15.70 0.09 0.1 07 14.97 1.584 15.81 0.09 0.11 07 15.55 1.591 15.98 0.1 0.13U 07 20.67 1.629 15.50 0.04 0.08U 07 34.01 1.741 15.69 0.08 0.1 U 07 34.01 1.741 15.69 0.08 0.1 U 07 34.52 1.750 15.94 0.08U 0.12U 07 36.64 1.769 15.93 0.09 0.12U