THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 25 Birch Street, Cambridge, MA 02138 USA Tel. 617-354-0484 Fax 617-354-0665 INTERNET: aavso@aavso.org * * * AAVSO NEWS FLASH * * * Subject: SN 1998S, AT Cnc, CH Cyg, V1504 Cyg, No. 271 AB Dra, AW Gem, V344 Lyr March 13, 1998 ________________________________________________________________________________ SUPERNOVA 1998S IN NGC 3877 We have been informed by the Central Bureau for Astronomical Telegrams (IAU Circular 6829) of Zhou Wan's discovery of a supernova in NGC 3877 on Mar 2.68 UT (date as corrected in IAU Circular 6835) at unfiltered CCD magnitude 15.2. No object was present on images taken on Feb. 23.7 (IAU Circular 6835). D. D. Balam, University of Victoria, has reported the following precise position (IAU Circular 6831): R.A. = 11h 46m 06.18s Dec. = +47 degrees 28' 55.5" (2000) The supernova has brightened considerably since its discovery as indicated by the following observations which have been reported to the AAVSO: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAR 07.32 13.0 MRV MAR 10.181 12.8 SPK MAR 08.085 12.8 MRV MAR 11.844 12.2 PYG MAR 09.947 12.9 PYG MAR 11.866 12.3 PYG MAR 10.017 12.2 GRL MAR 12.132 12.2 PYG MAR 10.044 12.2 GRL MAR 12.75 12.5 KIL MAR 10.098 12.3 GRL MAR 13.361 12.4 MRV For more information on this discovery please see AAVSO Alert Notice 244. This Alert Notice and a chart for SN 1998S are available from our FTP site: ftp.aavso.org (198.116.78.2), in /pub/alerts/alert244 This information may also be accessed through our Web site at the following address: http://www.aavso.org ----------------------------------------------------------------------------- AT CANCRI The dwarf nova type (Z Cam subclass) cataclysmic variable AT Cnc appears to be in outburst, as indicated by the following observations: AAVSO Observer UT Mag. Initials MAR 01.4639 14.2 SRX MAR 11.849 13.7 PYG ----------------------------------------------------------------------------- CH CYGNI The symbiotic variable CH Cyg, which had been recovering from its unprecedentedly faint minimum of June-July 1996 (see AAVSO Alert Notice 222 and News Flashes 28, 31, 32, 40,& 70), is now fading as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials JAN 01.68 9.0 GRL JAN 27.7201 9.3 TUB JAN 02.7708 9.2 TUB FEB 02.767 9.2 PYG JAN 02.810 9.1 PYG FEB 03.78 9.1 GRL JAN 03.81 9.0 GRL FEB 04.251 9.2 PYG JAN 05.7569 9.2 TUB FEB 15.15 9.4 GRL JAN 06.794 9.1 PYG FEB 16.79 9.3 GRL JAN 07.100 9.2 FRF FEB 22.19 9.6 GRL JAN 07.18 9.0 GRL FEB 23.81 9.6 GRL JAN 10.700 9.1 FRF FEB 25.79 9.6 GRL JAN 10.755 8.9 DPA FEB 28.02 9.7 GRL JAN 14.773 9.1 PYG FEB 28.5271 9.7 HSG JAN 15.1049 9.0 HSG MAR 01.5118 9.7 HSG JAN 16.766 9.1 PYG MAR 02.05 9.7 GRL JAN 16.7847 9.1 TUB MAR 03.5146 9.7 HSG JAN 17.90 9.1 GRL MAR 04.4750 9.7 HSG JAN 18.7187 9.0 TUB MAR 05.09 9.7 GRL JAN 19.0785 8.9 HSG MAR 07.13 9.7 GRL JAN 23.85 9.0 GRL MAR 08.5236 9.7 HSG JAN 25.0938 9.1 HSG MAR 08.5236 9.7 HSG JAN 25.7222 9.3 TUB MAR 12.105 9.7 PYG JAN 26.03 9.1 GRL For more information on CH Cyg please see AAVSO Alert Notice 244. This Alert Notice, charts for CH Cyg, and a light curve of CH Cyg (covering January 1993 to date) are available from our FTP site: ftp.aavso.org (198.116.78.2), in /pub/alerts/alert244 This information may also be accessed through our Web site at the following address: http://www.aavso.org ----------------------------------------------------------------------------- V1504 CYGNI The dwarf nova type cataclysmic variable V1504 Cyg appears to be in outburst, as indicated by the following observation: AAVSO Observer UT Mag. Initials MAR 12.181 14.4 PYG According to the AAVSO International Database this star is fainter than visual magnitude 15.7 during quiescence. ----------------------------------------------------------------------------- AB DRACONIS The dwarf nova type (Z Cam subclass) cataclysmic variable AB Dra is in outburst, as indicated by the following observations: AAVSO Observer UT Mag. Initials MAR 09.978 13.9 PYG MAR 10.5229 13.6 HSG MAR 11.861 13.0 PYG ----------------------------------------------------------------------------- AW GEMINORUM The dwarf nova type (SU UMa subclass) cataclysmic variable AW Gem appears to be in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAR 01.1403 <16.0 HSG MAR 09.974 <13.9 PYG MAR 03.1340 <15.2 HSG MAR 11.851 13.9 PYG MAR 04.4306 <14.5 HSG ----------------------------------------------------------------------------- V344 LYRAE The dwarf nova type (SU UMa subclass) cataclysmic variable V344 Lyr appears to be in outburst, as indicated by the following observations: AAVSO Observer UT Mag. Initials FEB 22.158 <15.5 PYG MAR 12.133 14.3 PYG ----------------------------------------------------------------------------- We thank the following contributors for the data that they have provided for this News Flash: DPA - A. Diepvens, Belgium MRV - R. Modic, USA FRF - R. Fidrich, Hungary PYG - G. Poyner, England GRL - B. Granslo, Norway SPK - P. Schmeer, Germany HSG - G. Hanson, USA SRX - R. Stubbings, Australia KIL - L. Kiss, Hungary TUB - V. Tuboly, Hungary 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 ________________________________________________________________________________ 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 sending a message to: observations@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 We look forward to including your observations in future editions of AAVSO NEWS FLASH! ______________________________________________________________________________