COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3366 Konkoly Observatory Budapest 16 August 1989 HU ISSN 0374-0676 NOTE ON CROSS-IDENTIFICATION OF FLARE STARS IN THE PLEIADES During analysis and supplementation of the machine-readable version of the Tonantzintla catalogue (TC) of Pleiades flare stars (Haro et al., 1982, Tsvetkov et al., 1987) a number of inconsistencies has been found which will be discussed in the following. I. We have noticed multiple designations of the same stars in the General Catalogue of Variable Stars (GCVS) (Kholopov, 1985) as well as in the New Catalogue of Suspected Variables (NCSV) (Kholopov, 1982) to which we would like to draw attention. We also used the 67th, 68th and 69th Name List of Variable Stars (Kholopov et al., 1985, 1987, 1989), for updates of GCVS designations. Table 1 lists all flare stars for which two different designations are given in the GCVS, and those for which designations are given is both the GCVS and the NCSV (in the case of LO Tau even two numbers in the NCSV). As communicated in the notes to the NCSV, such coincidences have been suspected for most of the stars listed in Table 1. They could, however, not be verified, because identification charts are often lacking in the publications announcing the discoveries of flare stars. Table 1. Pleiades flare stars with multiple designations in the GCVS and the NCSV TC GCVS Author Design. Name List NCSV Author No. No. in Name Lists of of Variable No. Designation Variable Stars Stars (No.) in NCSV 80 LO Tau T3 57 - - 80 - - - 01231 A112 80 - - - 01290 K25 150 V 438 Tau B179 58 - - 150 - - - 01256 K7 263 V 539 Tau T6b 59 - - 263 - - - 01298 B424 298 V 336 Tau T83 57 - - 298 - - - 01308 K3 400 V 337 Tau T164 57 - - 400 - - - 01370 A128 412 V 464 Tau B211 58 - - 412 - - - 01378 K4 451 V 565 Tau B233 59 - - 451 V 715 Tau A94 62 - - 509 V 692 Tau A113 60 - - 509 - - - 01420 B423 II. Some Pleiades flare stars in the Tonantzintla catalogue (included only in the NCSV) have shown only one flare of small amplitude which does not satisfy the criterion Delta m > 5 sigma(m) (Tsvetkov et al., 1988) so that there is reasonable doubt that they belong to the class of UV Cet stars. They are listed in Table 2. Table 2. Pleiades flare stars with single low amplitude flares, included only in the NCSV TC Author NCSV min Delta m No. Designation No. Pg Pg 1 A110 01202 16.3m 0.3m 99 A111 01235 15.8 0.4 120 A109 01242 16.2 0.3 293 B229 01314 17.0 0.5 III. Four flare stars from the TC, which have relatively large amplitudes and are identified on accompanying finding charts, have apparently neither GCVS nor NCSV designations. There are no well-founded reasons why these stars should not be included in the GCVS as UV Cet type stars. They are listed in Table 3. For the star TC87, which has shown two flares, the amplitude is given according to the original paper, because of a mistake in the TC. Table 3. Pleiades flare stars included neither in the GCVS nor in the NCSV TC Author min Delta m No. Designation U/Pg U/Pg 61 T69b 15.8mU 1.5mU 87 K*2 16.6U 1.6U 200 AB526 15.2 0.8 261 K*4 >20.0U >3.2U IV. Several stars are listed in the GCVS or NCSV with UV Cet identification, which are not included in the TC. They are given in Tables 4 and 5. For most of them, the GCVS lists the minimum brightness according to the photographic UBV photometry of Chavushian and Gharibjanian (1975). The maximum brightness is taken from the original papers. This procedures leads in some cases to larger amplitudes than those given in the original papers. We are inclined to think that this is caused by uncertainties in the determination of stellar magnitudes both at minimum and maximum brightness and is not due to an underlying type of variability. This effect may also apply to some of the remaining stars which are listed in the GCVS as UV Cet stars in the Pleiades region. In order to avoid systematic errors in amplitudes, the stellar magnitudes at minimum and the flare amplitudes were taken from the original papers, and are given in Table 4. The 5sigma criterion was applied to the magnitudes of the stars in this table; 6 stars were found which did not satisfy the criterion. This result, and also the fact that they are not included in the TC, sheds doubts on the reality of their variability. Table 4. Stars listed as UV Cet stars in the GCVS, but not in the TC GCVS Author H II min delta m Notes No. Designation Pg/U Pg/U LL Tau B128 17.0m >1.0m 1 V 354 Tau J&M 2082 15.31 0.88 2 V 385 Tau B124 15.0 0.5 3,4 V 393 Tau T59 15.5 0.7 U 1,3 V 394 Tau B126 14.7 1.2 4 V 447 Tau B206 1038 16.8 0.5 3 V 487 Tau B261 17.7 0.7 3 V 496 Tau B262 17.1 0.7 3 V 521 Tau T22b 628 16.0 U 0.8 U V 525 Tau B263 17.7 0.8 3 V 527 Tau T4b 979 17.8 U 1.1 U V 529 Tau T24b 1009 17.5 U 1.0 U V 560 Tau B295 3065 14.2 0.8 V 735 Tau K**1 18.5 U 1.8 U 1 V 736 Tau K**2 17.2 U 1.7 U 1 V 755 Tau K**4 19.3 U 4.3 U 1 V 792 Tau K#1 20.5 U 7.1 U 1 V 964 Tau K*K >18 U >2.6 U 5 V 965 Tau K*N >18 U >2.7 U 5 V 967 Tau K*Q >18 U >3.0 U 5 V 968 Tau K*O 16.2 U 2.9 U 5 V 970 Tau K*I >18 U >3.2 U 5 V 972 Tau K*E 17.5 U 1.9 U 5 V 973 Tau K*P >18 U >2.9 U 5 V 974 Tau K*G >18 U >2.6 U 5 V 975 Tau K*H >18 U >2.6 U 5 V 976 Tau K*J >18 U >2.2 U 5 V 977 Tau K*B >18 U >1.8 U 5 V 978 Tau K*L >18 U >3.0 U 5 V 979 Tau K*D >18 U >2.1 U 5 V 980 Tau K*A 17.5 U 2.5 U 5 V 981 Tau K*C 17.8 U 1.6 U 5 V 982 Tau K*M >18 U >2.7 U 5 V 983 Tau K*F >18 U >3.9 U 5 Table 5. Stars listed as probable UV Cet stars in the NCVS but not in the TC NCSV Author H II min delta m Notes No. Designation V/Pg/U V/Pg/U 01238 T37b 17.2m U 0.6m U 1,3 01281 799 13.71 V 0.15 V 2 01300 1403 14.9 0.3 3 01320 P1 15.3 V 0.5 V 1,3 01329 >18.5 >3.7 1,6 01336 >18.5 >3.3 1,6 01350 B345 17.2 1.2 01358 J&M 2407 13.6 0.8 2 01375 >18.5 >3.5 1,6 Notes to Tables 4 and 5: 1 Identification charts were not published. 2 Possible flare found during one photoelectric observation. 3 The amplitude of the flare does not fulfill the criterion Delta m > 5 sigma(m). 4 According to Ambartsumian et al. (1972) Haro was not convinced that B124 and B126 are flare stars. 5 UV type stars in the Pleiades region from the 69th Name List of Variable Stars. As a rule they all need more precise determination of the magnitude at minimum and of the amplitude. 6 Only one image is visible on the patrol plate and no star is found on the Palomar Observatory Sky Survey prints. V. We conclude that at least 8 of the more than 500 reported flare stars in the Pleiades region need unification of their designations in the GCVS and the NCSV. Four Pleiades flare stars should be included in the GCVS. 47 stars merit better observations to confirm their membership in the UV Cet class of variables, for 11 of them identification charts are needed. The authors wish to thank Professor Dr. W. C. Seitter and Dr. H. Duerbeck for useful suggestions and comments. M. K. T. also acknowledges support from the Alexander von Humboldt Foundation. KATYA P. TSVETKOVA and M.K. TSVETKOV* Department of Astronomy and National Astronomical Observatory Academy of Sciences, Sofia, Bulgaria and Astronomical Institute of Muenster University, F.R. Germany *Research fellow of the Alexander von Humboldt Foundation References: Ambartsumian, V. A., Mirzoyan, L. V., Parsamian, E. S., Chavushian, H. S., Erastova, L. K., Kazarian, E. S., Ohanian, G. B.,1972, Astrofizika, 8, 485. 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Rodono, Publ. Oss. Astrofis. Catania (in press). [BIBCODE 1988sasf.conf..147T ]