COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2635 Konkoly Observatory Budapest 4 December 1984 HU ISSN 0374 - 0676 STELLAR FLARES IN TAURUS Systematic multi-exposed photographic observations of the aggregate in Taurus (see Hojaev, 1983) have been continued. The observations were carried out with the 21" and 40" Schmidt telescopes of the Byurakan Astrophysical Observatory in January-December 1982. We utilized ORWO ZU-21 plates without filter. The effective time of the patrol is equal to 284.9 hours. The data concerning our observations are presented in Table I : the telescope used,the number of plates and exposures, effective time of observations and limiting magnitude of the plates. Table I Data concerning the observations ---------------------------------------------------------------- Telescope Number of Number of plates exposures t_eff m_pg lim. ---------------------------------------------------------------- 21" 218 1253 205h 35m 17.0 (1188 x10m+65x7m) 40" 148 855 75h 27m 17.5 (2x15m+2x10m+119x7m +6x6m+715x5m+11x3m) Total 366 2108 281h 02m In addition, eleven direct plates of the observed region were also used (T_eff=03h52m) Using these observations 32 flare stars and 37 suspected flares have been discovered the data on which are given in Tables II and III : Byurakan designation, coordinates for 1950.0, photographic magnitudes m_pg at minimum brightness, photographic amplitude of the observed flare delta m_pg, date of flare event, moment of maximum brightness (UT) and telescope. The stars showing brightness augmentation on two or more consecutive images (expositions) on our plates and having amplitudes more than 3sigma (often not less than 5sigma for the first of flare events) should be considered as certain flare stars. On the other hand the red dwarfs showing brightness augmentation of about 3sigma: or a strong brightness augmentation on one exposition only are considered as suspected flare stars. Table II. New flare stars ------------------------------------------------------------------------------ B No R.A. Decl. m_pg delta m_pg Date UT_max Telescope ------------------------------------------------------------------------------ 12 4h34m8 +24d47' 15.5m 1.4m 19. I.82 21h28m 21 13* 38.9 +25 18 17.1 2.3 24. I.82 19 28 21 14 32.4 +26 36 18.5 3.2 10. II.82 16 59 21 15 40.8 +26 24 18.7 2.9 13. II.82 15 37 21 16 33.6 +26 36 16.6 1.9 21. II.82 17 45 21 17 24.3 +22 11 15.6 1.4 22. II.82 18 24 21 18 35.5 +22 00 16.2 1.1 25. II.82 16 13 21 19 31.4 +22 22 16.1 1.4 27. II.82 17 14 21 20 39.7 +23 23 17.1 1.6 14. III.82 17 35 21 21 31.5 +22 19 15.9 1.1 15. IX.82 22 24 21 22 30.4 +22 29 16.7 1.1 17. IX.82 23 59 21 23 21.2 +22 48 20.5 4.2 18. IX.82 00 53 21 24 31.1 +25 15 19.1 3.9 24. IX.82 20 34 21 25 27.1 +25 43 17.3 1.4 24. IX.82 23 47 21 26 23.5 +26 28 18.6 2.4 28. IX.82 22 37 21 27 39.4 +24 44 17.2 1.2 30. IX.B2 00 41 21 28 30.7 +22 36 19.8 4.1 17. X.82 22 18.5 21 29 22.2 +21 56 16.2 1.4 22. X.82 20 57 21 30 23.3 +22 53 16.4 1.5 23. X.82 00 52 21 31 37.8 +22 46 17.2 3.6 25. X.82 21 17 40 32 23.8 +25 13 16.9 1.6 26. X.82 22 09 40 33 30.3 +24 16 17.2 1.2 26. X.82 23 31 40 34 24.6 +23 28 16.6 1.3 12. XI.82 22 23 40 35 33.8 +25 44 17.7 1.5 13. XI.82 22 28 40 36 26.8 +23 00 16.7 2.1 14. XI.82 20 22 40 37 25.6 +24 38 17.9 1.8 15. XI.82 00 35 40 38 27.3 +22 24 13.8 2.7 15. XI.82 00 45 40 39 23.6 +22 14 17.0 1.7 15. XI.82 02 10 40 40 31.3 +25 25 19.2 2.3 15. XI.82 20 16 40 41** 27.3 +25 03 16.0 1.5 15. XI.82 21 01 40 42 36.8 +23 49 17.3 1.3 17. XI.82 19 36 40 43 37.7 +22 57 16.4 1.3 18. XI.82 02 05 40 Remarks to Table II: * LkH_alpha 332/ G2- (Cohen and Kuhi, 1979) member Trapezium type Triplet (Hojaev, 1984) ** Star had another flare (see Table IV) during our observations. Table III. Suspected flare stars -------------------------------------------------------------------------------- SB No RA Decl. m_pg delta m_pg Date UT_max Telescope -------------------------------------------------------------------------------- 12 4h31.4m +23d56' 16.5m 0.9m 18. I.82 18h23m 21" 13 34.1 +26 30 15.8 0.9 19. I.82 21 38 21 14 31.7 +22 24 16.5 0.8 23. I.82 16 32 21 15 34.5 +24 01 16.9 1.9 23. I.82 18 05 21 16 22.2 +24 22 16.2 0.7 24. I.82 19 18 21 17 35.1 +23 54 16.0 0.8 13. II.82 15 52 21 18 31.1 +24 55 16.2 0.7 21. II.82 17 02 21 19 33.8 +25 51 16.7 1.3 22. II.82 18 44 21 20 37.4 +24 11 16.5 1.4 22. II.82 19 04 21 21 23.7 +24 45 16.0 0.7 24. II.82 18 11 21 22 30.4 +22 29 17.5 I.0 16. IX.82 00 40 21 23* 29.2 +23 46 16.7 0.5 16. IX.82 22 10 21 24 32.5 +26 03 17.2 0.6 17. IX.82 01 05 21 25 28.6 +25 27 17.3 0.7 18. IV.82 00 53 21 26 39.8 +25 59 16.4 0.8 20. IX.82 22 51 21 27 39.4 +24 17 16.8 1.0 24. IX.82 23 57 21 28 22.1 +23 58 17.2 1.0 28. IX.82 22 53 21 29 28.6 +25 24 16.6 1.1 28. IX.82 23 29 21 30 25.8 +24 21 16.7 0.8 12. X.82 20 44 21 31 25.9 +22 29 17.3 0.9 13. X.82 00 26 21 32 22.3 +23 49 16.6 1.1 13. X.82 21 46 21 33 30.5 +24 10 17.0 1.0 14. X.82 00 59 21 34 31.2 +23 30 17.3 0.6 17. X.82 21 27.5 21 35** 28.4 +25 39 17.3 0.9 12. XI.82 22 02 40 36 37.4 +24 37 16.1 0.5 13. XI.82 02 09 40 37 37.5 +23 16 15.6 0.7 13. XI.82 18 07 40 38 25.7 +24 58 16.7 1.0 13. XI.82 23 36 40 39 34.7 +23 49 15.2 0.5 14. XI.82 00 12 40 40 30.4 +23 22 16.2 0.9 14. XI.82 23 50 40 41 30.6 +24 23 16.0 0.9 15. XI.82 17 30 40 42 31.8 +23 44 16.3 1.0 15. XI.82 20 11 40 43 30.8 +24 42 16.5 0.8 15. XI.82 22 53 40 44** 35.8 +22 08 16.5 1.5 15. XI.82 23 45 40 45 18.2 +22 42 16.6 0.6 18. XI.82 00 31 40 46 26.7 +25 42 16.0 0.9 6.XII.82 16 11 40 47*** 29.7 +24 51 14.2 0.8 7.XII.82 16 10 40 48 35.8 +23 20 16.4 1.0 8.XII.82 17 20 40 Remarks to Table III: * Southern Component of the variable star SVS 2159 ** May be variable *** Star. No. 5 from Landolt's (1967) UBV standard sequence. During our observations five repeated flares of known and above mentioned flare stars were detected, the data of which are given in Table IV. In the last column of Table IV the reference to the designation is given. Table IV. Repeated flares ------------------------------------------------------------------------- Star m_pg delta m_pg Date UT_max Tel. References ------------------------------------------------------------------------- B4 20.0m 7.7m 17. I.82. 16h54m 21" Hojaev, 1983 FH 16.2 1.3 26.III.82. 17 30 21" Haro and Chavira,1955 Huang et al.,1979 EZ 17.7 2.2 22. X.82. 23 40 21" Haro and Chavira,1955 Erastova,1970 FI 17.8 1.4 25. X.82. 21 31 40" Haro and Chavira,1955 B41 16.0 1.8 7.XII.82. 17 34 40" present paper A more detailed analysis of our results will be published elsewhere. 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) A. S. HOJAEV Byurakan Astrophysical Observatory Armenia, USSR References: Cohen, M., Kuhi, L.V.,(1979) Ap.J.Suppl., 41, 743. [BIBCODE 1979ApJS...41..743C ] Erastova, L.K., (1970) Astrofizika, 6, 686. [BIBCODE 1970Afz.....6..686E ] Haro, G., Chavira, E., (1955) Bol.Obs.Tonantzintla No. 12, 3, [BIBCODE 1955BOTT....2l...3H ] Hojaev, A.S., (1983) I.B.V.S., No. 2412. Hojaev, A.S., (1984) Astrofizika (in press), Huang, C.C., Zhang, C.S., Wang, K.M., (1979) Acta astron.Sinica, 20, 332. [BIBCODE 1979AcASn..20..329H ] Landolt, A.V., (1967) A.J., 72, 1012. [BIBCODE 1967AJ.....72.1012L ]