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Alert Notice 156: 2027+52 Nova Cygni 1992 AND 0807-34 Nova Puppis 1991 AND Updates on Rare Dwarf Novae Outbursts AND Participation in Monitoring Cataclysmic Variables for EUVE Survey

THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
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Tel. 617-354-0484 FAX 617-354-0665

AAVSO ALERT NOTICE 156 (April 16, 1992)

2027+52 NOVA CYGNI 1992

This recent nova has been very well monitored by observers worldwide since its discovery in February. Accompanying is the light curve of N Cyg 92 from its discovery to April 12. Using the critera from The Galactic Novae, by C. Payne-Gaposchkin (Dover Publications, NY, 1964, p. 24), this nova would be classified as a fast nova (fall of two magnitudes in 11 to 25 days), for it took 18 days to decline two magnitudes, thus giving it a decline rate of 0.11 magnitude per day. Once it reached magnitude 6.3, N Cyg 92 took another 18 days to decline one magnitude, and thus the rate of decline decreased to 0.06 magnitude per day.

Also accompanying are 'b' and 'd' scale charts for Nova Cyg 92. Observers are requested to use these charts in making magnitude estimates.

It is interesting to note that one of the four amateur observing projects for the Hubble Space Telescope (Cycle I) is the monitoring of a bright nova to detect comet clouds around it. The amateur astronomer on this project, John Hewitt, has been waiting for a bright nova since the selection of his project for Cycle I over two years ago. N Cyg 92 has been chosen by John to be observed by HST, and it has been scheduled for observation in the coming weeks. Observers are strongly recommended to continue to keep a close eye on this nova so that we may provide information to John during his observing run. Please continue to call your observations in to Headquarters.

 

0807-34 NOVA PUPPIS 1991

N Pup 91, discovered in late December, has also been well monitored during the past few months. Accompanying is its light curve compiled from observations both telephoned to Headquarters and sent in with observers' monthly reports. N Pup 91 took 38 days to decline two magnitudes from maximum, with a decline rate of 0.05 magnitude per day. It is therefore a moderately-fast nova, again using Payne-Gaposchkin's classification of novae light curves (fall of two magnitudes in 26 to 80 days). Observers are strongly recommended to continue to keep a close eye on this nova.

 

UPDATES ON RARE DWARF NOVAE OUTBURSTS

0829+53  SW Ursae Majoris

This SU UMa-type dwarf nova had a superoutburst in which it reached magnitude 10.5 on March 21.154 UT, as reported by R. Stewart, W. Paterson, NJ. SW UMa remained brighter thatn magnitude 12 until March 31, and declined to <13.7 by April 5.9 UT.

1950+32A EY Cygni

This dwarf nova, at quiescence since 1986, had an outburst in which it reached 11.0 on March 28.1 UT, as reported by P. Schmeer, Bischmisheim, Germany, and 11.5 on March 29.4, as independently reported by J. Griese, Stamford, CT. This outburst was well-monitored by observers world-wide. EY Cyg was magnitude 13.1 on April 12.

 

PARTICIPATION IN MONITORING CATACLYSMIC VARIABLES FOR EUVE SURVEY

We are in the process of compiling the finder charts of cataclysmic variable for which we will be coordinating observations worldwide for NASA's EUVE (Extreme Ultraviolet Explorer) satellite. We will be alerting observers and interested participants about this project soon, giving chart information for this very interesting pioneering satellite project, which, starting in late summer, will survey the sky in the extreme ultraviolet wavelengths (70-760 Angstroms).

The answering machine (617-354-0484) at AAVSO Headquarters is on nights and weekends for your convenience.

Thank you very much for all your efforts and valuable observations.

Good observing!

Janet A. Mattei
Director

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