COMMISSIONS 27 AND 42 OF THE IAU INFORMATION BULLETIN ON VARIABLE STARS Number 3764 Konkoly Observatory Budapest 7 September 1992 HU ISSN 0374 - 0676 NEW FLARE STARS AND REPETITIONS IN THE ORION ASSOCIATION REGION Photographic material of the Orion association from Tonantzintla Schmidt plates covering the interval 1978-1982 and re-examination of old plates allowed us to find 20 new stars and 20 flare-ups of known flare stars. The effective observational time is 104 hours. Table 1 New flare stars in Orion association No. Star R. A. Dec. U DeltaU Spec. Date of Ref. Ton Parenago 1900 1900 mag mag type flare 340 5h22.4m -5d45' 16.7 1.3 27.01.65 341 24.5 -7.28 16.8 2.8 21.01.82 342 25.4 -6.33 >18.4 >3.4 03.01.82 343 26.4 -6.09 >18.4 >3 22.01.82 344 27.4 -6.38 >18.6 >2.6 05.02.65 345 28.0 -6.10 >18.4 >3.9 26.10.81 346 1062 28.0 -4.51 16.8 2.6 26.10.81 347 28.9 -7.20 >18.5 >2.8 29.12.64 348 29.0 -4.25 17.6 0.5 26.01.65 349 V 1118 29.R -5.38 >18.8 >2.0 ealpha 07.02.67 1, 2 350 1631 29.9 -4.33 16.2 1.6 19.01.66 351 30.4 -4.20 >18.6pg >2.2pg 21.10.62 352 2220 30.9 -4.02 16.1 0.6 10.01.82 353 31.0 -4.17 >18.4 >2.4 24.12.65 354 32.3 -4.05 18.2 2.8 11.02.78 355 2612 33.0 -6.43 15.2 2.9 26.01.82 356 33.2 -5.05 16.5 0.9 ealpha 21.01.82 3 357 2685 33.6 -5.07 15.0 1.3 07.01.81 358 35.2 -5.36 17.0pg 0.9pg 23.10.62 359 37.4 -5.31 16.6 0.9 23.01.82 References: 1. Gasparian et al. (1990) 2. Parsamian et al. (1991) 3. Parsamian, Chavira (1982) Table 2 Repeated flares in Orion association No. Star U DeltaU Spec. Date of Ref. Ton Parenago mag mag Type Flare 12 17.3 2.1 ealpha 19.01.82 1 71 17.5 2.0 23.01.82 143 1502 17.6 1.5 ealpha 21.01.82 150 18.3 2.9 2.01.82 176 16.8 0.8 ealpha 29.12.81 2 219 1609 16.8 2.2 19.01.82 224 1790 16.2 1.1 23.12.81 257 17.2 1.9 08.01.65 260 17.4 1.9 29.01.65 294 18.5 2.7 14.02.66 296 17.3 2.1 13.12.72 328 2186 17.2 4.3 ealpha 31.01.81 1 333 2326 16.0 2.4 ealpha 24.01.82 1 349 V1118 >18.8 >2.6 ealpha 12.01.77 3, 4 349 V1118 >18.8 >3.1 ealpha 11.01.81 350 1631 16.2 0.8 24.12.76 * V1143 18.6 ealpha 20.01.63 4, 5 V1143 18.6 2.0 07.04.88 4 AB 18 18.0 1.0 28.12.59 AB 105 16.1 0.9 13.12.72 References: 1. Haro (1953), 2. Haro (1976), 3. Gasparian et al. (1990), 4. Parsamian et al. (1991b), 5. Marsden (1983). * This flare was observed spectroscopically. The results obtained from the present examination and re-examination are given in Tables 1 and 2. In the columns of Tables 1 and 2 the following data on flares are presented respectively: the Tonantzintla number of stars, number from Parenago's catalogue, the approximate equatorial coordinates, ultraviolet magnitude at minimum, the amplitude of flare event, the spectral type, the date of flare. Flare ups of stars T12 and T143 can be considered as slow ones. In Table 1 we continue the Tonantzintla numeration (Parsamian et al., 1978). Recently re-examination of all photographic material covering essentially the interval from 1959 to 1978 allowed us to find 33 new flare stars and 83 repetitions. The new ones received numbers Ton 261-298 (Chavira, Parsamian, 1991). Some numbers of Ton do not exist at all, they are 255, 256, 258, 259, 299-325 and T278=T142, T282=B19, T284=U7, T286=R5, T289=AB17. A more detailed article is going to appear in Rev. Mexicana Astron. Astrof. E. CHAVIRA G. GONZALEZ C. ESCAMILLA Instituto Nacional de Astrofisica, Optica y Electronica Tonantzintla, Mexico E. PARSAMIAN Byurakan Observatory, Armenia, Instituto Nacional de Astrofisica, Optica y Electronica Tonantzintla, Mexico References: Chavira, E., Parsamian, E., 1991 Rev. Mexicana Astron. Astrof. 22, 15 [BIBCODE 1991RMxAA..22...15C ] Gasparian L. G., Melikian A. S., Oganian G. B., Parsamian E. S., 1990 Flare Stars in Star Clusters and Solar Vicinity, ed. Mirzoyan L. V., IAU Symp. No. 137, 253, Byurakan [BIBCODE 1990IAUS..137..253G ] Haro G., 1953 Ap. J. 117, 73 [BIBCODE 1953ApJ...117...73H ] Haro G., 1976 Bol. Inst. Tonantzintla, 2, 3 [BIBCODE 1976BITon...2....3H ] Marsden B. G., 1983 IAU Circ., No. 3771 [BIBCODE 1983IAUC.3771....2I ] Parsamian E., Chavira E., Gonzalez G., 1978 Bol. Inst. Tonantzintla, 2, 341 [BIBCODE 1978BITon...2..341P ] Parsamian E., Chavira E., 1982 Bol. Inst. Tonantzintla, 3, 69 [BIBCODE 1982BITon...3...69P ] Parsamian E. S., Ibragimov M. A., Oganian G. B., Gasparian K. G., 1991a Astrofizika Parsamian E., Gasparian K. G., Oganian G. B., Chavira E., 1991b Astrofizika [BIBCODE 1991Afz....34..175P ]