.po 0 THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 25 Birch Street, Cambridge, MA 02138 USA BITNET: aavso@cfa SPAN: cfa::aavso INTERNET: aavso@cfa.harvard.edu Tel. 617-354-0484 FAX 617-354-0665 AAVSO ALERT NOTICE 196 (January 12, 1995) OUTBURST OF 2110+13 EF PEGASI We have been informed by Patrick Schmeer (Bischmisheim, Germany) that the cataclysmic variable EF Peg is in outburst, as indicated by the following observations: Jan 5.732 UT, <13.0 (Schmeer); 9.988, <13.5 (J. Bortle, Stormville, NY); 11.726, 11.1 (Schmeer); 11.740, 11.1 (Schmeer); 11.744, 11.1 (Schmeer). The outburst was confirmed by G. Poyner (Birmingham, England) on Jan 11.744 UT at 11.1. EF Peg is in the dwarf nova class of cataclysmic variables. Within that class, it is an SU Ursae Majoris-type star. Until recently, EF Peg was a poorly- studied dwarf nova, with a large amplitude, varying from about 18th magnitude to about 10.9. Its last superoutburst was also first detected by P. Schmeer on October 15, 1991, when it reached 10.9. The superoutburst, which was the first visually-detected and well-monitored superoutburst, lasted about three weeks, and during this superoutburst, S. Howell et al. observed superhumps with a period of 2.09 hours. From this information they estimated the orbital period of the system to be 2.05 hours (see Howell, S. B., Schmidt, R., DeYoung, J. A., Fried, R., Schmeer, P., Gritz, L. 1993, P.A.S.P., 105, 579; Howell, S. B., and Liebert, J., 1994, IBVS, No. 4073; Gessner, H., 1988, IBVS, No.3209, for discussions on photometry of 1991 superoutburst, spectroscopy, and outburst interval length, respectively). Please monitor the current outburst (possibly a superoutburst, since it is bright) of EF Peg, using the accompanying f scale (5"/1mm) AAVSO preliminary chart, and report your observations to AAVSO Headquarters. EF Peg has a close companion about 5 arcseconds away at position angle 305 degrees. Be particularly careful of this companion, and when reporting magnitude estimates of EF Peg during outburst, indicate whether your estimate is a combined magnitude or not. During quiescent intervals, make sure of the identification of EF Peg. Some observers are reporting EF Peg at about 12.4 during quiescence - this magnitude estimate is that of the companion and not of EF Peg. The history of the preliminary AAVSO finder chart for EF Peg is rather interesting. The first preliminary chart was issued by C. Ford in March 1973, and it was revised in August 1976. However, the comparison star magnitudes in this old chart, mostly visual estimates, were too bright. In October 1991, a revised preliminary AAVSO chart was issued by C. Scovil, on which the photovisual magnitudes of the comparison stars around the variable as well photoelectric magnitudes from Geneva Observatory of some bright stars were given. Later, T. Kato and T. Takata of Kyoto, Japan, obtained CCD(V) magnitudes for closeby comparison stars, and the AAVSO preliminary chart was revised in June 1993 to include these CCD(V) magnitudes and photoelectric and photovisual magnitudes from the 1991 chart. In addition to the AAVSO finder chart, a chart with a similar (but not the same) sequence has been issued by The Astronomer (TA). Schmeer, who used the TA sequence, informed us that the 10.5 star on the accompanying AAVSO chart is 10.8 on the TA chart; AAVSO 10.2 is TA 10.6; AAVSO 11.4 is TA 11.3; and AAVSO 12.1 is TA 12.4. It is essential that observers indicate the source and date of the finder chart and the comparison stars used in the observations they report to the AAVSO. This star is a good example of the essential need for observers to have the most recent charts issued for the stars they are observing, and of the inhomogeneities that exist in the variable star data files from the different comparison star magnitudes coming from different sources. Both the observers and those of us from different associations/groups working with the charts and the data are aware of this situation, and we are trying to find a solution so that all observers will use the same sequence for a star. Until a solution is found, however, it is CRUCIAL that observers indicate the source and date of each chart they are using. REQUEST TO MONITOR SOME HIPPARCOS RED VARIABLES FOR PHOTOMETRIC CALIBRATION Astrometric and photometric data from the Hipparcos satellite, which operated between August 1989 and August 1993, are now being processed so that they can be made public by the end of 1996. Throughout the mission, AAVSO data on long period variables were used in order to predict the brightness of these variables so that the correct amount of satellite time could be allocated for their observation. In order to calibrate the satellite photometry of red variables, multicolor data are needed. While CCD and photoelectric photometry are being carried out on some of the red variables, we have been requested to provide visual data on these stars in order to check the calibration. Observers, particularly those in the southern hemisphere, are strongly recommended to monitor as many of the stars listed below as possible once a week throughout January and February, and report their observations to Headquarters as early as possible. If you need finder charts for any of the stars, please let us know by telephone, email, or fax, and we will provide them free of charge. Range | Range Desig. Star Type Period max min|Desig. Star Type Period max min | 0010-32 S SCL M 362.5 6.7 12.9|0617-02 V MON M 340.5 7.0 13.2 0016-20 T CET SR 158.9 5.0 6.9|0653-08 V523 MON SR 45. 7.0 7.5 0022-12 AG CET SR 90. 7.0 7.5|0656-14 RV CMA L 8.6 9.8 0122-33 R SCL SR 370. 6.6 9.0|0705-58 AC CAR SR 99. 7.6 8.8 0214-03 OMI CET M 331.9 3.6 9.2|0702-07 RY MON SR 455.7 7.5 9.2 0243-12 Z ERI SR 80. 5.5 7.1|0718-25 VY CMA 6.5 9.6 0247-08 RR ERI SR 97. 5.9 7.7|0724-04 RX MON M 345.7 8.8 13.9 0250-50 R HOR M 407.6 6.0 13.1|0731-73 S VOL M 394.8 8.8 13.5 0301-59 V HOR SR 7.2 8.3|0753-43 SU PUP M 339.8 8.5 13.5 0328-26 RZ FOR SR 64.6 7.7 8.5|0806-37 AS PUP M 324.6 8.2 10.7 0343-07 BR ERI SR 175.5 6.9 8.2|0812-13 SV PUP M 166.5 8.0 11.4 0351-24 T ERI M 252.2 8.0 12.8|0824-05 RT HYA SR 290. 7.0 10.2 0359-16 V ERI SR 97.0 7.3 8.9|0841-27 R PYX M 364.7 9.0 12.4 0417-05 RW ERI SR 91.4 8.7 10.2|0925-51 Y VEL M 449.9 8.8 13.6 0437-38 R CAE M 390.9 8.1 13.1|0929-62 R CAR M 308.7 4.5 9.7 0443-36 T CAE SR 156. 6.5 8.4|0930-14 X HYA M 301.1 8.3 12.8 0500-22 T LEP M 368.1 8.2 12.9|0945-01 W SEX SR 134.0 7.9 10.1 0504-05 SY ERI SR 96.0 8.0 8.9|0946-22 Y HYA SR 302.8 6.5 9.0 0508-48 S PIC M 428.0 8.0 13.4|0951-41 X VEL SR 140. 8.7 9.9 0506-11 RX LEP SR 60. 5.0 7.4|1006-61 S CAR M 149.4 5.7 8.6 0515-33 T COL M 225.8 7.5 11.9|1011-53 W VEL M 394.7 8.8 13.3 0524-04A S ORI M 414.3 8.6 13.0|1016-34 V ANT M 302.7 8.3 13.0 0540-46 W PIC L 7.1 10.2|1029-83 X OCT SR 206.8 7.2 11.2 0543-31 S COL M 325.8 9.3 13.4|1044-53 WX VEL M 411.5 1 0.5 12.1 0548-01 NSV 2721 L |1046-20 V HYA SR 530.7 7.0 13.0 0601-24 S LEP SR 89.0 6.0 7.6|1150-58 W CEN M 201.5 8.4 13.2 Many thanks for all your efforts and your astronomical contributions. Best wishes to your loved ones for a very happy and fulfilling new year, with clear skies and good observing! Janet A. Mattei Director