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: 0749+22 U GEM IN OUTBURST No. 585 FUSE SATELLITE SCHEDULED TO OBSERVE March 2, 2000 ---------------------------------------------------------------------------- ASTRONOMERS WILL OBSERVE CURRENT OUTBURST OF U GEM WITH THE FAR ULTRAVIOLET SPECTROSCOPIC EXPLORER(FUSE) SATELLITE! Thanks to observations of the current outburst of U Gem which were reported to the AAVSO and included in AAVSO News Flash No. 584, colleagues from the Space Telescope Science Institute and Johns Hopkins University will be observing U Gem with the Far Ultraviolet Spectroscopic Explorer(FUSE) satellite starting Saturday, March 4th. Your observations will enable us to determine whether this outburst is narrow or wide so that we can then pass this information on to our colleagues. Astronomers plan to monitor U Gem periodically throughout the current outburst. The data that you provide will be vital in scheduling the satellite time and will be used to correlate with the satellite data. Please monitor U Gem closely throughout the current outburst. Below are the observations that we have received so far of the current outburst of U Gem: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials FEB 29.1819 14.5 HSG MAR 01.7889 12.3 CMG FEB 29.1875 14.2 SXN MAR 01.799 12.1 MUY FEB 29.4500 14.0 SRX MAR 01.801 12.1 MGH FEB 29.4917 14.1 NLX MAR 01.810 12.1 SPK FEB 29.837 <13.3 WWJ MAR 01.823 12.1 WWJ FEB 29.923 13.7 MGH MAR 01.868 11.6 MUY FEB 29.967 14.1 PYG MAR 01.9111 11.7 CMG MAR 01.0257 13.6 DPL MAR 01.9313 10.8 CMG MAR 01.0403 13.8 BRJ MAR 01.934 11.0 MUY MAR 01.0736 13.7 BRJ MAR 01.964 10.7 PYG MAR 01.1611 13.5 MKJ MAR 02.1014 10.2 HSG MAR 01.4472 13.4 SRX MAR 02.1257 10.0 HSG MAR 01.4708 13.4 SRX MAR 02.1292 9.9 DKS MAR 01.4986 13.3 SRX MAR 02.2167 9.6 HAB MAR 01.5569 13.3 SRX MAR 02.2174 9.6 HSG MAR 01.764 12.2 SPK MAR 02.4222 9.3 SRX U Gem has fairly deep (0.5 magnitude) eclipses of the "hot spot" on the accretion disk by the cool companion. We strongly recommend that visual and particularly CCD observers monitor these eclipses. The eclipses last only about 10 minutes. They are widest right after the eruption, and gradually narrow down with time, being the narrowest just before the eruption. Magnitude estimates of the eclipses should be made every minute and recorded to four places of the decimal of the JD. The eclipses have the following elements (J. Smak 1993, Acta Atronomica, 43, 121): HJD Primary Minimum = HJD 2437638.82627 + 0.1769061898 * E, (+/- 8) (+/- 30) where E is the cycle number. Please send your observations of U Gem soon after the end of your observing session if possible, so that we can keep our colleagues well informed of the status of this outburst. ---------------------------------------------------------------------------- We thank the following contributors for the data that they have provided for this News Flash: BRJ - J. BORTLE, USA MUY - E. MUYLLAERT, BELGIUM CMG - G. COMELLO, NETHERLANDS NLX - P. NELSON, AUSTRALIA DKS - S. DVORAK, USA PYG - G. POYNER, ENGLAND DPL - P. DOMBROWSKI, USA SPK - P. SCHMEER, GERMANY HAB - R. HAYS JR., USA SRX - R. STUBBINGS, AUSTRALIA HSG - G. HANSON II, USA SXN - M. SIMONSEN, USA MGH - H. MCGEE, ENGLAND WWJ - W. WILSON, ENGLAND MKJ - J. MCKENNA, USA 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! ____________________________________________________________________________