COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 141 Konkoly Observatory Budapest 30 June 1966 LONG PERIOD VARIABLE STARS WITH LARGE INTRINSIC POLARIZATION The polarimetric observations of long period variable stars made by the writer until the beginning of March 1966 were published recently (Ap. J., 144, 857, 1966). In the accompanying table some new observations are listed which were made with the 21-inch telescope of the Lowell Observatory using Polaroid J-filter as an analyser. In this table P and Theta denote the percentage polarization and position angle of the plane of vibrations in the equatorial coordinates, respectively; the superscripts V and B denote the yellow and blue filters of the UBV photometric system. The stars V Canum Venaticorum and Z Ursae Majoris, both having periods slightly shorter than 200d, reached the maximum polarization when they were at minimum brightness. The variables RS Cancri, R Leonis, and U Herculis were least polarized at maximum brightness. The full list of the polarimetric observations of red variable stars made in the present programme will be published in a Lowell Observatory Bulletin. Date Percentage Postion Spectral 1966 Polarization Angle HD Star Type Period (U.T.) V PV PB ThetaV ThetaB 41698 S Lep M6 90d Mar.21 7.1 1.8 2.6 51deg 56deg 44639 V Mon M5e-M8e 335 Feb.23 9.4 0.9 1.8 27 11 Mar.22 7.9 1.0 2.0 9 12 78712 RS Cnc M6 Ib - 120 Mar.16 5.9 0.5 0.8 53 58 II (S) and Mar.17 5.9 0.5 0.5 54 62 1700 Apr.14 5.5 0.1 0.2 50 33 Apr.25 5.5 0.2 0.3 12 175 84748 R Leo M7e-M8e 313 Mar.17 6.1 0.5 0.4 16 43 92763 R UMa M3e-M6e 302 May 23 7.0 0.8 0.8 48 51 June 17 7.1 0.4 0.5 42 34 103681 Z UMa M5 IIIe 198 Mar.22 7.7 0.9 1.1 8 3 Mar.29 7.8 0.8 1.0 10 10 Apr.13 8.2 1.0 1.4 38 42 Apr.25 8.5 1.3 2.4 54 47 May 16 9.1 1.4 2.6 41 41 June 14 8.4 0.2 0.4 56 4 June 17 8.3 0.4 0.6 57 34 108105 SS Vir Vir Ne 355 Apr.11 6.6 0.1 0.8 176 14 (C6 e) May 15 7.4 0.3 0.9 167 3 June 14 7.2 0.1 0.9 5 7 115898 V CVn M4e-M6e 192 Mar.15 8.2 5.4 7.2 102 100 Mar.17 8.2 5.4 7.1 101 98 Mar.29 8.0 5.1 6.4 103 99 Apr. 9 7.8 4.7 5.5 104 102 Apr.11 7.8 4.5 5.4 103 103 Apr.17 7.8 4.2 4.7 105 103 Apr.26 7.6 3.3 3.8 102 101 May 15 7.5 3.1 3.3 104 103 June 13 6.8 2.3 2.7 103 109 120499 R CVn +/ M6e-M8e 328 May 16 8.9 0.9 l.5 27 23 June 13 7.7 1.0 1.5 22 30 136753 S CrB M6e-M8e 361 Mar.18 6.1 1.0 1.4 163 167 Mar.29 6.2 0.8 1.4 161 163 Apr.11 6.4 0.6 1.2 157 159 Apr.17 6.7 0.6 l.1 154 162 May 16 7.7 0.6 1.4 152 159 June 17 8.8 0.4 1.3 143 152 141826 V CrB N2(C6_2)e 358 Mar.18 8.6 2.0 2.2 147 142 Apr.14 8.9 1.8 1.8 148 160 144205 X Her M6e 95 Apr.18 6.7 1.2 1.6 59 57 and May 22 6.4 0.7 0.8 60 54 746 June 14 6.4 0.0 0.3 73 179 148206 U Her M7e-M8e 406 Apr.24 9.1 l.7 4.5 155 148 Apr.25 9.0 1.6 4.2 149 154 May.15 8.5 0.6 1.1 125 165 May.23 8.5 0.3 0.2 132 153 June 14 8.9 0.7 1.9 68 52 186686 RT Cyg M2e-M4e 190 Mar.29 8.6 ... 0.3 ... 47 Apr.16 7.6 0.2 0.2 163 22 Apr.25 7.0 0.1 0.4 47 34 May 15 7.0 0.1 0.2 43 56 June 17 8.3 0.2 ... 155 ... 187796 Chi Cyg S7e-510e 407 May 15 6.2 1.6 2.1 88 82 May 23 6.4 1.5 1.9 91 84 June 17 7.2 1.2 1.2 92 79 +/ Appreciable polarization of R CVn was first noticed by T. Gehrels in April 1966. June 21, 1966 Lowell Observatory Flagstaff, Arizona K. SERKOWSKI