COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2412 Konkoly Observatory Budapest 14 October 1983 HU ISSN 0374-0676 FLARE STARS IN TAURUS According to the regular search program of flare stars in stellar aggregates (Ambartsumian and Mirzoyan, 1971; Haro, 1976) we began systematic photographic monitoring observations by the multiexposure method (see, for example, Haro, 1968) in the region of the Taurus dark cloud complex. The observations were carried out with the 21 in. Schmidt telescope of Byurakan Astrophysical Observatory on ORWO ZU-21 plates with 2-mm Schott filter GG 385 (B-light) and without filter (Pg-light). These observations were made during the period between October 1980 and December 1981. The observations covered a field 4.75d x 4.75d around the star BD +23d705 (R.A. = 04h30m, Decl. = +24d10', 1950.0) (stellar association Taurus T 3). The multiexposure plates usually contained a series of six-exposures of 5 or 10 minutes each. The total patroling time is equal to 127.87 hours. The data on our observations including the number of plates, exposures and effective time of observations are presented in Table I. Table I Observational Material ------------------------------------------------------------------- Light Number of Number of T_eff Mean limiting plates exposures magnitude ------------------------------------------------------------------- B 38 226 35h02m 16.5m-17.0m (192x10m+28x5m+6x7m) Pg 101 569 92h50m 17.0m (545x10m+24x5m) ------------------------------------------------------------------- Total 139 795 127h52m ------------------------------------------------------------------- Eleven new flare stars were discovered and some suspected flare events were detected. Data for the observed flare stars and suspected flare stars are given in Table II and Table III,correspondingly. In successive columns of these Tables the following data are presented: 1. Byurakan designation 2-3. Coordinates (1950.0) 4-5. Photographic magnitude at minimum and photographic amplitude of the observed flare 6. Date of flare event 7. Moments of maximum brightness of stars (UT). Table II New Flare Stars ------------------------------------------------------------------------------ No. R.A. Decl. m_pg Delta m Date UT(max) 1950.0 ------------------------------------------------------------------------------ B1 4h19.8m +25d28' 17.5m(B)* 2.3m 18/19.X.80 23h16.5m B2 4 21.5 23 48 17.1(B)* 1.1 28/29.I.81 17 23 B3 4 29.7 22 36 18.5(B)* 1.7 29/30.I.81 18 06.5 B4 4 25.2 24 18 20 5.1 5/6.II.81 18 00 B5 4 40.9 22 17 18.8 4.2 6/7.II.81 15 47 B6 4 31.8 26 28 17.1 1.2 6/7.II.81 20 15 B7 4 23.3 24 35 17.4 1.5 27/28.II.81 18 22 B8 4 22.7 21 51 19.5 5.0 9/10.III.81 17 54 B9 4 29.8 26 28 20.5 5.5 25/26.III.81 18 32 B10 4 28.2 26 25 20 5.3 30.IX/1.X.81 21 05 B11 4 32.4 22 54 17.8 2.2 22/23.X.81 01 56 ------------------------------------------------------------------------------ Table III Suspected Flare Stars ------------------------------------------------------------------------------ No. R.A. Decl. m_pg Delta m Date UT(max) 1950.0 ------------------------------------------------------------------------------ SB1 4h23.5m +24d28' 16.9m(B)* 0.7m 27/28.I.81 17h05m SB2 4 21.5 23 45 17.3(B)* 0.4 28/29.I.81 17 23 SB3 4 21.4 24 45 16.9(B)* 0.6 28/29.I.81 18 03 SB4 4 31.3 23 02 17.0(B)* 0.8 29/30.I.81 18 54 SB5 4 34.5 21 51 15.7 0.7 3/4.II.81 16 37 SB6 4 31.4 26 27 18.2 2.4 4/5.III.81 16 45 SB7 4 32.4 21 54 17.5 1.5 9/10.III.81 17 44 SB8 4 27.1 22 53 16.4 1.0 9/10.III.81 18 04 SB9 4 33.2 26 16 16.6 1.6 25/26.III.81 17 27 SB10 4 34.9 22 59 17.2 0.9 2/3.X.81 23 23 SB11 4 33.5 23 29 17.5 1.5 26/27.X.81 01 03 ------------------------------------------------------------------------------ * The observations were made in B light. A. S. HOJAEV Byurakan Astrophysical Observatory, Armenia, USSR References: Ambartsumian, V.A., Mirzoyan, L.V.: 1971, in New Directions and New Frontiers in Variable Stars Research, I.A.U. Colloquium No. 15., Veroff, Bamberg, vol. 9, 98. [BIBCODE 1971ndnf.coll...98A ] Haro, G.: 1968, in Stars and Stellar Systems, vol. 7, eds. B.M. Middlehurst, L.H. Aller, Univ. of Chicago Press, Chicago, 141. [BIBCODE 1968nim..book..141H ] Haro, G.: 1916, Bol.Inst.Tonantzintla, vol. 2, No. 1, 3, [BIBCODE 1976BITon...2....3H ] [From IBVS 2635] Erratum : in the previous paper (Hojaev, 1983) the coordinates of the flare star B11 were given erroneously. The correct coordinates are as follows : R.A. = 4h31m.4, Decl. = 21d54'(1950.0)