Alert Notice 157: 1700-43 Probable Nova in Scorpius AND 2027+52 Nova Cygni 1992 AND Data support for satellite observations of cataclysmic variables

25 Birch Street, Cambridge, MA 02138 USA
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Tel. 617-354-0484 FAX 617-354-0665

AAVSO ALERT NOTICE 157 (May 28, 1992)


The Central Bureau for Astronomical Telegrams (IAU Circulars 5526, 5528) has informed us of the photographic discovery of a probable nova in Scorpius by Paul Camilleri, Cobram, Vic, Australia, on May 22.492 UT at photovisual magnitude 8.2. The precise 1950 position of the probable nova is

R.A. 17 03 42.69   Dec. -43 11 26.5

Recent observations include:
Apr. 28.600 UT, <12 photovisual (P. Camilleri);
May 22.492, 8.2 photovisual (Camilleri);
23.511, 8.3 photovisual (Camilleri);
24.371, 8.3 visual (P. Williams, Heathcote, NSW, Australia);
24.425, 8.4 visual (Camilleri);

The accompanying 'aa' scale AAVSO chart shows the location of the probable nova. Please use this chart, along with the accompanying sequence for RS Sco, to make your estimates. Please telephone your observations in to AAVSO Headquarters, so we may inform the astronomical community.

Our congratulations to Paul on his latest discovery!

2027+52 NOVA CYGNI 1992

Nova Cyg 92 continues to fade, and is presently in the mid-8th magnitude range. Accompanying is a revised 'd' chart for N Cyg 92. Four of the comparison stars on the 'd' chart dated 3/92 have been measured photoelectrically by B. Skiff and the magnitudes adjusted. A fifth magnitude on this chart has also been revised. The revised comparison stars are:

Old  New    Old New      Old     New     Old    New      Old    New
8.8  9.2V     9.7 10.1V    110.8  11.0     11.2  11.3V     13.0  12.8V

Please use this revised chart to observe the nova. If you have made observations using any of the comparison stars whose magnutudes have been changed, please revise your estimates and re-submit them to AAVSO Headquarters, making sure to indicate that they are revised estimates.


Astronomers scheduled to observe the cataclysmic variables listed below with the Hubble Space Telescope (HST) and the International UIltraviolet Explorer (IUE) have requested our assistance in closely monitoring these stars and informing them of their behavior so they can observe them at the appropriate times.

1. Observations with HST

0749+22 U Gem and 0409-71 VW Hyi

For the next 6 months, astronomers will be interested in observing the white dwarf component of these close binary systems while the systems are in quiescence. Using the long-running AAVSO data base we have predicted the "best" times for the astronomers' observations with HST. In order to confirm and/or revise these predictions, it is essential to know when U Gem and VW Hyi have outbursts from now until January 1993.

Please monitor these stars whenever they are observable, and call in your observations to Headquarters when either star has an outburst.

2318+17 IP Peg

A larg consortium of astronomers will be studying the cataclysmic variable IP Peg with HST for a year, beginning in July. They would like to know when the outbursts occur as they plan to follow it through an outburst cycle. They are depending on you for earth-based monitoring and immediate notification of its outbursts.

Please monitor IP Peg whenever it is observable, and call in your observations to Headquarters when it has an outburst.

2. Observations with IUE

1137+72 YY Dra and 1129-11 TT Crt

Astronomers are planning to observe these two cataclysmic variable with the IUE in the coming year, beginning in June. They are depending on you for any alert to the rather infrequent outbursts of these stars, so they may schedule the IUE to obtain UV observations at critical times.

Please monitor these stars and inform Headquarters of any outburst activity.

0900-31 T Pyx

This recurrent nova, whose last outburst occurred in December 1966, is overdue for an outburst. Please monitor it closely, and call Headquarters when the eruption occurs, as astronomers are interested in observing it with the IUE at this time. Observers beware - there is a near-by variable star possibly in the magnitude 13-15 range which has misled observers of T Pyx in the past!

If you need finder charts for the above stars, please write to HQ and request copies, which will be sent free of charge. Your calls to HQ in connection with the above requests will be reimbursed by the astronomers, so please send in copies of pertinent telephone bills.

As always, your observations of these objects and immediate outburst information are vital to the scheduling of the satellites and the success of the projects. Please monitor the above-mentioned stars closely and call in your observations of their ourbursts to Headquarters. Then aswering machine (617-354-0484) in on nights and weekends for your convenience.

I would like to share with you an excerpt from a letter from an astronomer who has utilized our support services in his satellite research: "I am writing to convey my deepest gratitude for the indispensable observational ground-support your organization has provided and will continue to provide for my [HST] project...The recent information on the detailed outburst histories of VW Hyi and U Gem were absolutely essential to scheduling and carrying out my time-critical HST experiments successfully... Without your data support and continued monitoring by your ground-based observes, scientific progress in understanding cataclysmic variable would be well-nigh impossible..."

Your astronomical efforts truly are appreciated! Good observing!

Janet A. Mattei

files: Nova Sco 1992 'aa' scale chart; Nova Cyg 1992 'd' scale chart; RS Sco 'd' scale chart w/annotated sequence



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