THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 25 Birch Street, Cambridge, MA 02138 USA Tel. 617-354-0484 Fax 617-354-0665 http://www.aavso.org * * * AAVSO NEWS FLASH * * * Subject: 1813-25B V4641 SGR 2002+33 V1363 CYG No. 1212 August 7, 2003 ---------------------------------------------------------------------------- 1813-25B V4641 SAGITTARII The microquasar V4641 SGR is in outburst. Microquasars are a class of X-Ray novae. Their X-Ray and optical emissions are thought to be from an accretion disk around a neutron star or black hole. The most recent bright outburst of this object to be reported to the AAVSO International Database occurred in May 2002 and was reported in AAVSO News Flash No. 969. Below are recent observations showing the current outburst: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials JUL 21.7640 13.4 MLF AUG 02.4690 13.2 SRX JUL 22.4260 13.4 SRX AUG 02.6810 13.4 SRX JUL 25.4210 13.4 SRX AUG 04.1153 12.34 CCDV WJD JUL 27.4180 13.4 SRX AUG 04.9396 11.8 AAX AUG 01.3760 12.1 SRX AUG 04.9590 11.8 AAX AUG 01.4840 13.3 SRX AUG 06.4220 11.5 SRX AUG 01.5210 13.4 SRX AUG 07.3021 12.8 LMK AUG 01.5430 13.5 SRX AAVSO 'd' and 'e' scale charts (11/99 revision date) can be downloaded from the AAVSO web site. Simply go to http://www.aavso.org/observing/charts/ and type in the object name to locate the charts. This object can exhibit significant magnitude variations within minutes. Please continue to keep a very close eye on this very unusual and interesting object. Be sure to report the time of your observations to 4 decimal places indicating which chart and comparison stars have been used. ---------------------------------------------------------------------------- 2002+33 V1363 CYGNI The dwarf nova type (Z CAM subclass) cataclysmic variable V1363 CYG appears to be in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials JUL 30.2903 <15.1 SXN AUG 02.9431 <14.5 GCO JUL 31.9368 <13.9 OJR AUG 02.9950 14.9 PYG JUL 31.9563 <14.5 GCO AUG 03.9860 14.9 PYG AUG 01.9417 <14.5 GCO AUG 06.0208 14.8: GCO ---------------------------------------------------------------------------- We thank the following contributors for the data that they have provided for this News Flash: AAX - A. AMORIM, BRAZIL PYG - G. POYNER, ENGLAND GCO - C. GUALDONI, ITALY SRX - R. STUBBINGS, AUSTRALIA LMK - M. LINNOLT, USA SXN - M. SIMONSEN, USA MLF - I. MONARD, SOUTH AFRICA WJD - J. WEST, USA OJR - J. OSORIO, SPAIN Please monitor these and other variable stars closely and phone-in, fax, or e-mail your observations to the AAVSO. Good observing! Janet A. Mattei, Director Rebecca Pellock, Technical Assistant ____________________________________________________________________________ Symbols may include: < = fainter than magnitude given (variable not seen) : = uncertain CCDV = Charge-coupled device with (V) filter If you would like to contribute to AAVSO NEWS FLASH, please send observations of unusual variable star activity to: observations@aavso.org Those who wish to subscribe (free of charge) or unsubscribe to NEWS FLASH may do so by visiting the following web page: http://www.aavso.org If you would like data from the AAVSO International Database for research purposes, please send your request to: Janet Mattei, AAVSO Director, at aavso@aavso.org An archive of past issues of the News Flash is available at the following web page: http://www.aavso.org/newsflash/ We look forward to including your observations in future editions of AAVSO NEWS FLASH! ____________________________________________________________________________