COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 715 Konkoly Observatory Budapest 1972 September 12 NEW FLARE STARS IN THE PLEIADES REGION (A Re-examination of the Tonantzintla Photographic Material: 1963-1970) The continued re-examination of all our multiple exposure photographic material obtained during the years 1963 through 1970 at the Tonantzintla Observatory on the Pleiades region (Haro and Gonzalez 1970) has been exhaustively completed and we have found - apart of a large number of flare-up repetitions in the already known flare stars discovered at the Asiago, Byurakan and Tonantzintla Observatories - 12 new flare stars that for one reason or other escaped detection in our previous works. The results are summarized in Table 1, in which a provisional new serial numbering is used adding a b to each number in order to distinguish the new flare stars from the ones listed and numbered before. This has been done because there is certain confusion and mixing-up in the serial numbers published by different Observatories. In a general catalogue that is under preparation by one of the authors (G.H.) we will put together all the flare stars found in the Pleiades region at various Observatories, using a more definitive serial numbering that will be arranged in order of increasing right ascension and avoiding, as far as possible, different numbers for the same star or repeating the same number for distinct flare stars. In Table 1 the stars 2b and 6b have shown two flare-ups. The star 9b corresponds to HII2034 which is up to now the brightest flare star, at minimum, in the Pleiades (V = 12.57) and probably with a spectral type as early or earlier than K3. We erroneously communicated to Dr. Rosino the serial number of flare star 11b as No. 12 and he found a flare repetition of the same star, numbering it as 83. The many flare-up repetitions found in the previously known flare stars will be published in a future paper. Table 1. New Flare stars in the Pleiades Region 1963-1970 ------------------------------------------------------------------------------- No. Star R.A. Dec. Mag.in U Delta mU Date of (1900) (1900) at minimum Flare-up h m ------------------------------------------------------------------------------- 1b 3 33.6 +23d11' 16.6 0.8 6 Feb.1970 2b 3 33.8 23 36 20.5 6.3 22 Nov.1963 2b_ 3 33.8 23 36 20.5 3.5 26 Nov.1963 3b 3 36.2 23 53 18.4 2.5 21 Dec.1968 4b HII-979 3 40.4 24 08 17.8 1.1 27 Oct.1968 5b 3 41.3 22 03 21.0 5.1 10 Nov.1963 6b 3 41.5 24 51 19.5 5.1 11 Nov.1963 6b_ 3 41.5 24.51 19.5 2.7 20 Nov.1968 7b 3 42.7 23 55 18.8 3.4 12 Jan.1970 8b 3 42.7 24 43 18.5pg. 1.0pg. 26 Oct.1968 9b HII-2034 3 42.8 23 40 14.2 0.8 6 Nov.1966 10b 3 42.9 22 35 18.9 3.8 14 Nov.1969 11b 3 45.9 25 30 20.0 4.5 16 Dec.1968 12b 3 47.3 + 25 38 18.3 3.1 14 Jan.1969 ------------------------------------------------------------------------------- August 28, 1972 G. HARO and G. GONZALEZ Instituto Nacional de Astrofisica Optica y Electronica Tonantzintla, Mexico References: 1 Haro, G. and Gonzalez, G. 1970. Bol. Obs. Ton. y Tac. 34, 191. [BIBCODE 1970BOTT....5..191H ]