COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1517 Konkoly Observatory Budapest 1978 December 19 INTERMEDIATE BAND AND H_beta PHOTOMETRY OF ULTRASHORT PERIOD CEPHEIDS For a discussion published elsewhere (Eggen 1979) of ultrashort period cepheids (USPC) observations of several such objects south of declination +30d were obtained with the 0.6, 0.9, 1.0 and 1.5 m reflectors at Cerro Tololo. These results are listed in Table 1 and the ephemerides used in computing phases are discussed in the notes to the table. Figures 1-6 show the run of magnitude and color indices with phase for representative stars. The rise from minimum to maximum light of GP And was followed in V on 11 August 1978 with the results shown in Figure 1. This segment of the light curve is shown as a continuous curve in Figure 2. The mean light curve in V for V 567 Oph in Figure 3 is from Clube et al. (1969) after shifting phase by -0.345 periods. The mean visual light curve of TV Lib in Figure 4 is also from Clube et al. SX Phe was also followed in V during the rising branch of the light curve on 15 September 1978 and all of the visual magnitude determined on that date are shown in Figure 5. The observations of most of these stars have been already been discussed (Eggen 1979) but those of BS Aqr were made subsequent to that discussion because of inconsistencies in the then available data. The present observations are shown in Figure 6. The difficulties encountered in the previous discussion were (1) the values of (b-y), beta, and M_1 were inconsistent and (2) the path traced by the variable in the (beta, [C_1]) plane was more representative of a low mass, halo cepheid such as RR Lyr, then of a high mass, old disk cepheid such as GP And. However the new observations, between phase 0.1 and 0.65 days, in Figure 7 lie on a path parallel to the main sequence relation and to the path of GP And. From the calibration discussed in the previous paper this leads to a median M_V = +0.35 mag, giving (U, V, R) = [+35, -58, -73) km sec^-1 and the variable is a high mass, old disk population cepheid. The values of (beta, b-y) indicate little or no reddening and deltaM_1 = 0.015 mag, compared with the Hyades stars. OLIN J. EGGEN Cerro Tololo Inter-American Observatory* La Serena, Chile References: Clube, S.V.M., Evans, D.S., and Jones, D.H.P. 1969, Mem.Roy. Astr.Soc., 72, 201 [BIBCODE 1969MmRAS..72..101C ] Eggen, O.J. 1971, Pub.A.S.P., 83, 762 [BIBCODE 1971PASP...83..762E ] Eggen, O.J. 1977, Pub.A.S.P., 89, 205 [BIBCODE 1977PASP...89..205E ] Eggen, O.J. 1979, Ap.J., (in press) * Cerro Tololo Inter-American Observatory is supported by the National Science Foundation under contract No. AST 74-04128. TABLE 1 Observations of USPC -------------------------------------------------------------------------------- Var V b-y M_1 C_1 beta J.D. Phase 244 -------------------------------------------------------------------------------- GN And* 5.20m 0.170m 0.165m 0.863m 2.752 2 obs. GP And* 10.65 0.098 0.168 1.003 2.848 3727.858 0.137 10.98 0.214 0.145 0.790 2.727 3728.833 0.529 10.82 0.172 0.139 0.914 2.789 3729.864 0.323 10.82 0.162 0.138 0.913 2.806 3730.858 0.265 11.03 0.201 0.160 0.705 2.712 3731.830 0.618 10.53 0.093 0.178 1.012 2.862 3731.864 0.051 GP And B 12.50 0.364 0.141 0.439 3 Obs. V1208 Aql 5.55 0.158 0.190 0.990 2.795 3734. 5.53 0.157 0.190 0.990 2.796 3735. V 1208 Aql B 9.06 0.245 0.195 0.600 2 Obs. BS Aqr* 9.57 0.219 0.160 0.846 2.696 3774.672 0.605 9.57 0.245 0.151 0.846 2.691 3774.679 0.641 9.60 0.245 0.157 0.829 2.697 3774.686 0.676 9.62 0.258 0.145 0.822 2.687 3774.696 0.727 9.28 0.150 0.195 0.925 2.765 3774.740 0.949 9.19 0.146 0.170 1.049 2.797 3774.754 0.020 9.23 0.149 0.173 1.032 2.789 3774.767 0.086 9.29 0.145 0.182 0.999 2.758 3774.778 0.141 9.33 0.163 0.169 0.984 2.756 3774.788 0.192 - Ari* 6.73 0.168 0.210 0.890 2.771 3727.875 6.71 0.184 0.195 0.895 2.778 3728.885 - Ari* A 6.74 0.187 0.113 0.871 2.738 3727.910 6.69 0.183 0.119 0.876 2.726 3728.910 - Ari B 8.35 0.192 0.160 0.710 2.744 2 obs. YZ Cap* 11.36 0.201 0.144 1.075 2.779 3727.754 0.583 11.41 0.222 0.089 1.157 2.750 3729.733 0.164 11.09 0.150 0.131 1.203 2.942 3729.722 0.780 11.60 0.238 0.111 1.020 2.746 3730.743 0.514 11.49 0.221 0.092 1.106 2.740 3731.757 0.222 V 743 Cen 8.71 0.195 0.159 0.862 2.765 3727.525 8.71 0.180 0.168 0.858 2.770 3728.548 8.80 0.192 0.164 0.844 2.758 3729.524 V 753 Cen* 10.64 0.216 0.147 1.034 2.728 3727.510 0.693 10.29 0.110 0.176 1.187 2.815 3730.469 0.061 10.65 0.220 0.121 1.038 2.769 3731.476 0.610 V 668 Cr A* 8.70 0.118 0.212 1.002 2.885 3727.625 8.71 0.112 0.206 1.011 2.878 3728.663 8.71 0.111 0.210 1.011 2.875 3729.670 8.71 0.101 0.216 1.010 2.870 3730.719 V 648 Her 6.86 0.096 0.218 0.869 2.844 3727.555 6.86 0.109 0.215 0.855 2.846 3728.555 6.86 0.103 0.213 0.870 2.833 3729.503 TV Lib* 11.66 0.123 0.132 1.036 2.833 3727.525 0.094 12.39 0.316 0.141 0.775 2.662 3729.538 0.560 12.13 0.237 0.138 0.926 2.764 3730.555 0.332 11.26 0.070 0.121 1.196 2.862 3731.545 0.004 V 747 Mon 6.11 0.200 0.190 0.800 2.738 2 Obs. ZZ Mic* 9.38 0.133 0.189 0.893 2.814 3728.767 0.668 9.30 0.109 0.165 1.002 2.864 3729.788 0.865 9.31 0.109 0.171 0.979 2.842 3730.795 0.854 9.57 0.157 0.161 0.868 2.762 3731.778 0.486 BP Oct 6.46 0.190 0.205 0.722 2.780 3 Obs. V 567 Oph* 11.38 0.439 0.140 0.833 2.757 3727.566 0.830 11.19 0.395 0.103 1.030 2.817 3728.569 0.544 11.31 0.434 0.113 0.914 2.757 3729.552 0.103 11.41 0.450 0.125 0.934 2.762 3730.566 0.902 11.24 0.408 0.115 0.978 2.811 3731.569 0.616 NZ Pav 6.05 0.185 0.185 0.800 2.745 3 Obs. DH Peg* 9.75 0.248 0.101 1.095 2.756 3702.830 0.388 9.31 0.163 0.121 1.277 2.837 3719.778 0.804 9.70 0.212 0.110 1.218 2.794 3727.796 0.098 9.34 0.158 0.119 1.321 2.826 3728.750 0.831 9.35 0.163 0.131 1.248 2.844 3729.775 0.843 9.30 0.174 0.109 1.255 2.857 3730.778 0.768 9.37 0.166 0.129 1.256 2.842 3731.764 0.627 DY Peg 10.58 0.251 0.110 0.793 2.750 3728.803 0.560 10.05 0.130 0.164 1.027 2.893 3729.778 0.930 10.27 0.153 0.143 0.991 2.862 3730.810 0.081 10.62 0.235 0.130 0.803 2.762 3731.792 0.547 SX Phe* 7.42 0.169 0.142 0.756 2.754 3766.705 0.691 7.15 0.086 0.178 0.921 2.858 3766.726 0.073 7.20 0.101 0.160 0.911 2.827 3766.731 0.164 7.20 0.130 0.151 0.853 2.800 3766.734 0.218 7.33 0.132 0.152 0.848 2.787 3766.736 0.255 7.36 0.149 0.144 0.821 2.763 3766.740 0.327 7.40 0.155 0.238 0.807 2.758 3766.742 0.370 7.44 0.163 0.133 0.774 2.746 3766.747 0.455 7.05 0.081 0.168 0.948 2.863 3773.705 0.046 7.25 0.120 0.155 0.868 2.800 3773.712 0.173 7.35 0.148 0.136 0.829 2.776 3773.715 0.228 7.36 0.155 0.141 0.806 2.762 3773.717 0.264 7.40 0.165 0.132 0.800 2.744 3773.719 0.301 7.43 0.170 0.135 0.779 2.740 3773.722 0.355 7.45 0.184 0.122 0.771 2.740 3773.724 0.392 7.46 0.181 0.135 0.739 2.739 3773.727 0.446 V 703 Sco* 7.88 0.248 0.165 0.793 2.738 3727.618 7.84 0.222 0.161 0.888 2.747 3728.597 7.86 0.228 0.157 0.858 2.741 3729.635 7.91 0.225 0.165 0.836 2.738 3730.680 7.91 0.243 0.150 0.848 2.739 3731.608 - Sco 7.41 0.090 0.171 1.033 2.867 3727.611 (HD 153747) 7.43 0.091 0.161 1.044 2.879 3728.590 7.42 0.093 0.163 1.029 2.851 3729.583 7.64 0.102 0.160 1.029 2.862 3730.594 XX Scl 8.92 0.130 0.201 0.944 2.815 3727.924 8.92 0.140 0.180 0.958 2.824 3728.851 8.93 0.144 0.180 0.942 2.820 3729.903 8.93 0.124 0.202 0.929 2.808 3730.910 V 369 Sct 9.38 0.311 0.153 0.868 2.730 3728.625 9.39 0.324 0.144 0.826 2.718 3729.639 9.42 0.312 0.160 0.848 2.712 3730.691 9.43 0.327 0.156 0.825 2.740 3731.614 AP Ser A* 11.38 0.219 0.111 0.961 2.742 3727.465 0.953 11.41 0.252 0.084 0.924 2.691 3728.479 0.943 11.41 0.228 0.086 0.967 2.702 3729.476 0.867 11.38 0.216 0.092 0.982 2.717 3730.479 0.814 11.37 0.227 0.093 0.999 2.685 3731.496 0.816 CW Ser* 11.95 0.206 0.180 0.852 2.720 3727.496 0.387 12.08 0.265 0.142 0.861 2.714 3729.496 0.674 11.75 0.207 0.153 0.934 2.789 3729.489 0.923 11.89 0.192 0.193 0.878 2.796: 3730.507 0.305 12.15 0.242 0.178 0.846 2.707 3731.510 0.608 V 479 Tau A 7.39 0.239 0.193 0.846 2.730 3 Obs. BC 8.88 0.205 0.199 0.800 2.807 3 Obs. BS Tuc 7.50 0.150 0.144 0.814 2.750 2 Obs. FG Vir 6.55 0.160 0.175 0.855 2.755 1 Obs. ---------------------------------------------------------------------- Notes to Table 1 ---------------- GN And Replaces the misprinted results in Eggen (1977) GP And Max=J.D.2433861.430+0.07868270d. Epoch modified to fit present maximum. BS Aqr Max=J.D.2443774.750+0.197822776d. Present epoch of max. - Ari HD11285 - Ari B HD1516514. Cpm companion, 74 arcsec. YZ Cap Max=J.D.2439025.749+0.2734585d. The period needs correction. V 753 Cen Max= J.D.2441386.144+0.221349d. V 668 CrA Replaces less accurate photometry with an 0.4m reflector (Eggen 1971). TV Lib Max= J.D.2420017.3015+0.269624031d. ZZ Mic Max= J.D.2440442.8443+0.0671835d. V 567 Oph Max= J.D.2438641.315+0.1300305d. SX Phe Max= J.D.2443766.722+0.054964379d. DH Peg Max= J.D.2427695. +0.25551267d. V 703 Sco The light amplitude is strongly variable and evidently near minimum at the time of the observation. AP Ser A Max= J.D.2428334.279+0.254118d. CW Ser Max= J.D.2431212.280+0.1891505d. BS Tuc Replaces less accurate photometry with an 0.4m reflector (Eggen 1971). [FIGURE 1] Fig. 1 - The rise to maximum light of GP And on 11 August 1978. [FIGURE 2] Fig. 2 - The light and color curves of GP And. The continuous curve represents the observations in Figure 1. [FIGURE 3] Fig. 3 - The light and color curves for V 567 Oph. The continuous curve represents the mean light curve by Clube et al. (1969) shifted by -0.345 periods. [FIGURE 4] Fig. 4 - The light and color curves for TV Lib. The continuous curve is the mean light curve by Clube at al. (1969) [FIGURE 5] Fig. 5 - Visual magnitudes of SX Phe on 15 September 1978. [FIGURE 6] Fig. 6 - Light and color curves for BS Aqr. [FIGURE 7] Fig. 7 - BS Aqr and the known, high mass cepheid GP And (Eggen 1979) in the (beta, [c_1]) plane; the main sequence is also indicated.