COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2636 Konkoly Observatory Budapest 4 December 1984 HU ISSN 0374 - 0676 NEW FLARE STARS IN TAURUS After our previously published observations (Hojaev, 1983, 1984) we continued the systematic search for flare stars in the Taurus dark clouds (TDC) region. The photographic multi-exposed observations were made with the 40" and 21" Schmidt telescopes of the Byurakan Astrophysical Observatory in pg-band (without filter) and with the 40" telescope in U-band (through a 2mm thick Schott UG1 filter) using ORWO ZU-21 plates. The patrol covered the period from January 1983 to April 1984 in the main. Several pg-plates obtained with the 21" telescope in 1980 (t_eff =01h30m) and U-plates obtained with the 40" telescope in 1981-82 (t_eff =06h45m) not used in our previous papers (Hojaev 1983, 1984) were also included. Total patrol time is equal to 304.02 hours. The data on the above-mentioned observational material (telescope, spectral band, the number of plates and exposures, effective patrol time and limiting magnitude on plates) are presented in Table I. Table I --------------------------------------------------------------------------- Observational Material Band Number of Number of Exposures T_eff m_lim Telescope Plates --------------------------------------------------------------------------- 21" Pg 219 1322 218h52m 17.0 (1302x10^m+6x7^m+14x5^m) 40" Pg 85 480 40h41m 17.5 (3x10^m+20x7^m+450x5^m+7x3^m) 40" U 46 257 41h15m 17.0-17.5 (5x15^m+228x10^m+24x5^m) Total 350 2059 300h48m In addition to the multi-exposed material, eight direct plates of the observed field with various exposure time (t_eff=03h13m) were also utilized 33 new flare stars and 39 suspected flare stars were found Data on these results are presented in Table II and Table III, respectively, Table II New Flare Stars in Taurus --------------------------------------------------------------------------- No. R.A. Decl. m delta_m Date UT_max Telesc. --------------------------------------------------------------------------- 44 04h40.0m +23d35' 15.7pg 1.5pg 3. I.83 17h49m 21" 45 04 31.5 +23 53 17.2pg 2.2pg 3. I.83 18 39 21" 46 04 21.7 +23 41 20.0pg 5.6pg 9. I.83 19 57 21" 47 04 35.3 +22 58 15.3pg 1.2pg 10. I.83 17 23 21" 48 04 22.6 +22 42 16.5pg 1.5pg 10. I.83 17 33 21" 49 04 21.4 +26 08 16.8pg 1.6pg 10. I.83 18 54 21" 50 04 22.3 +24 10 20.0pg 5.7pg 12. I.83 22 38 21" 51 04 35.6 +23 37 18.0pg 2.0pg 13. I.83 16 12 21" 52 04 33.3 +23 23 16.0pg l.9pg 2. II.83 18 36 21" 53 04 23.7 +22 24 16.9pg 2.2pg 7.III.83 15 53 21" 54 04 29.8 +22 13 16.7pg 2.0pg 11.III.83 18 17 21" 55 04 23.5 +22 26 16.9pg l.7pg 6. IX.83 23 20 21" 56 04 24.2 +25 14 17.1pg l.5pg 7. X.83 00 31 21" 57 04 41.2 +25 37 20.0pg 4.2pg 7. X.83 01 42 21" 58 04 33.4 +24 29 19.5pg 2.4pg 12. X.83 23 08 40" 59 04 30.0 +26 07 21.0pg 5.5pg 13. X.83 19 50 40" 60 04 31.9 +22 14 16.7pg 2.2pg 14. X.83 22 54 40" 61 04 30.4 +25 28 19.6pg 5.3pg 16. X.83 22 15 40" 62 04 24.7 +23 52 15.7 U 1.1 U 2. XI.83 21 57 40" 63 04 27.8 +22 48 15.6 U 2.5 U 3. XI.83 01 01 40" 64 04 38.4 +22 59 15.9 U 2.9 U 3. XI.83 02 15 40" 65 04 23.1 +23 58 16.3 U 1.4 U 10. XI.83 19 15 40" 66 04 36.7 +22 57 16.2 U 1.5 U 10. XI.83 19 25 40" 67 04 22.3 +23 27 17.2 U 1.7 U 10. XI.83 21 24 40" 68 04 23.7 +25 26 16.1 U 1.1 U 4.XII.83 21 19 40" 69 04 24.9 +23 55 17.0pg 1.3pg S.XII.83 21 04 21" 70 04 38.4 +22 29 17.1 U 1.9 U 9.XII.83 20 40 40" 71 04 31.7 +24 40 18.8pg 3.8pg 11.XII.83 22 53 40" 72 04 31.8 +22 16 17.5pg 1.9pg 11.XII.83 23 43 40" 73* 04 28.3 +24 05 16.1pg 2.1pg 14.XII.83 23 44 40" 74 04 34.3 +22 55 19.5pg 3.4pg 26.XII.83 15 31 40" 75 04 28.0 +24 44 18.0pg 4.3pg 26.XII.83 16 54 40" 76 04 30.9 +25 02 17.0pg 1.7pg 5. I.84 15 45 21" * Lk H_alpha 331 (Herbig and Rao, 1972) Table III Suspected Flare Stars in Taurus --------------------------------------------------------------------- No. R.A. Decl. m delta_m Date UT_max Telesc. --------------------------------------------------------------------- 49 04h30.8m +24d47' 15.2pg 0.5pg 10. I.83 22h58.5m 21" 50 04 26.1 +22 11 16.4pg 1.2pg 2. II.83 16 43 21" 51 04 32.9 +23 34 16.1pg 1.1pg 3. II.83 16 33 21". 52 04 33.8 +26 17 15.1pg 0.9pg 4. II.83 15 30 21" 53 04 30.3 +25 32 15.4pg 0.7pg 31.III.83 16 44 21" 54 04 32.1 +24 42 15.9pg 0.5pg 5. IV.83 16 59 21" 55 04 28.1 +23 56 16.1pg 0.7pg 5. IX.83 22 44 21" 56 04 26.6 +25 25 16.7pg 1.9pg 10. IX.83 23 02 40" 57 04 22.2 +23 51 16.9pg 1.0pg 10. IX.83 23 32 40" 58 04h28.4m +22d58' 16.9pg 1.3pg 10. I.83 23 37 40" 59 04 24.3 +25 01 16.6pg 0.9pg 6. X.83 21 08 21" 60 04 33.7 +26 12 15.9pg 0.8pg 7. X.83 20 30 21" 61 04 27.7 +24 14 17.3pg 1.8pg 7. X.83 22 51 21" 62 04 39.4 +22 40 20.5pg 3.7pg 10. X.83 01 20 21" 63 04 33.6 +26 08 16.9pg 0.6pg 11. X.83 22 30 21" 64 04 22.2 +24 22 18.3pg 1.7pg 12. X.83 22 08 40" 65 04 35.8 +22 52 16.9pg 0.8pg 13. X.83 19 55 40" 66 04 26.0 +23 29 16.9pg 0.8pg 13 X.83 20 56 40" 67 04 22.4 +24 03 17.0pg 0.8pg 14 X.83 00 35 40" 68 04 22.3 +24 02 17.0pg 0.8pg 14. X.83 00 50 40" 69 04 32.8 +23 15 16.9pg 0.7pg 14. X.83 22 20 40" 70 04 31.4 +23 54 16.6pg 0.6pg 16. X.83 22 10 40" 71 04 26.0 +25 14 16.1U 0.9 U 2. XI.83 22 07 40" 72 04 28.8 +22 43 16.2U 0.9 U 5. XI.83 21 57 40" 73 04 29.1 +25 17 15.9U 1.0 U 13. XI.83 22 32 40" 74 04 29.2 +22 29 17.7pg 1.0pg 12.XII.83 22 59 40" 75 04 25.5 +23 56 17.2pg 1.8pg 13.XII.83 00 37 40" 76 04 22.3 +25 13 16.1pg 1.3pg 13.XII.83 00 47 40" 77 04 25.7 +22 28 15.8pg 0.6pg 15.XII.83 00 44 40" 78 04 37.5 +23 23 15.8pg 0.9pg 22.XII.83 15 08 40" 79 04 36.0 +24 22 16.7pg 0.8pg 23.XII.83 17 30 40" 80 04 26.6 +22 56 16.9pg 0.9pg 24.XII.83 17 05 21" 81 04 29.9 +24 03 16.9pg 0.7pg 15.XII.83 18 30 21" 82 04 30.1 +23 37 17.0pg 1.1pg 26.XII.83 20 39 40" 83 04 25.2 +24 08 17.1pg 1.5pg 4. I.84 18 12 21" 84 04 25.8 +24 06 16.8pg 1.0pg 6. I.84 17 42 21" 85 04 32.2 +22 33 16.9pg 1.3pg 23. I.84 20 03 21" 86 04 27.9 +24 17 16.7pg 0.8pg 24. I.84 17 18 21" 87 04 31.7 +23 45 17.0pg 0.8pg 24. I.84 18 20 21" Successive columns of these tables give the following data: 1. Byurakan designation, 2-3. coordinates (1950.0), 4-5. magnitude at minimum and observed flare amplitude, 6-7. date of flare and moment of maximum brightness (UT), 8. telescope. Seven repeated flares were detected on six known, newly discovered flare stars and suspected flare stars. Data on these events are summarized in Table IV. Table IV Repeated Flares in Taurus Star m delta_m Date UT_max Tel. Reference B 4 20m Pg 4m1Pg 9. I.83. 19h 1m 21" Hojaev(1983,1984) SB42 16.3Pg 1.0Pg 7. X.83 23 33 21" Hojaev 1984 B 27 17.2Pg 1.0Pg 11. X.83 23 30.5 21" Hojaev 1984 SB65 16.9Pg 0.9Pg 13. X.83 21 11 40" present paper B 4 21.0U 5.8U 5. XI.83 20 42 40" Hojaev(1983,1984) and present paper SB38 16.7Pg 1.1Pg 25.XII.83 19 02 21" Hojaev (1984) EY 16.5Pg 0.7Pg 26.XII.83 15 36 40" Haro and Chavira (1955) Table IV contains data similar to those in Tables II and III omitting the coordinates. The references to the designation are presented in the last column. Because the star B4 was fainter than the limit of our photometric U-plates its m_U was evaluated assuming U-B= +1. At present the number of the known flare stars in the investigated region in TDS, is equal to 89. Seven flare stars showed 2 flares, two stars 3 and one star (B4) 4 flares. The lower limit of total number of the flare stars in this region estimated by Ambartsumian's (1969) formula is equal to 535. The discussion on flare stars in Taurus will be published elsewhere. The author is indebted to Dr. H.S. Chavushian for checking and confirming the above results. A.S. HOJAEV Byurakan Astrophysical Observatory USSR, Armenia, 378433 References: Ambartsumian V.A., 1969, Stars Nebulae and Galaxies, Byurakan Symposium, Academy of Sciences of Armenian SSR, Yerevan, p. 283, Haro G., Chavira E., 1955, Bol.Obs.Tonantzintla, 12, 3. [BIBCODE 1955BOTT....2l...3H ] Herbig G.H., Rao K.N., 1972, Ap.J., 174, 401. [BIBCODE 1972ApJ...174..401H ] Hojaev H.S., 1983, I.B.V.S., No. 2412. Hojaev H.S., 1984, I.B.V.S., No. 2635.