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Alert Notice 343: Rare outburst of 2320-08 EG Aquarii

November 10, 2006

Object: 2320-08 EG AQUARII

Coordinates: R.A. = 23h 25m 19.17s Decl. = -08o 18' 18.9" (USNO-B1.0, 2000)
Other (2000) positions reported include:
23:25:19.20 -08:18:18.9 (P. Schmeer, measurement of Univ. Iowa image)
23:25:19.20 -08:18:19.2 (A. Imada)
23:25:19.21 -08:18:19.6 (Henden and Sumner)

As announced in AAVSO Special Notice #24 (November 8, 2006) by Arne Henden and in Central Bureau Electronic Telegram 734 (Daniel W. E. Green, Editor), the dwarf nova EG Aqr was reported in outburst by Rod Stubbings, Tetoora Road, Victoria, Australia, at visual magnitude 12.4 on November 08.48 UT, and was confirmed by Hiroyuki Maehara, Japan, at 13.08V on November 08.62986 UT. This outburst is only the third observed.

Previous outbursts of EG Aqr (= USNO-B1.0 0816-0716959, minimum magnitude ~18.5 pg) occurred in October-November 1958 (observations at photographic magnitudes 14.8 and 14.0) and August 1959 (photographic magnitudes 14.0, 17.2, and decline to minimum).

CCD observations by several observers, including Tonny Vanmunster, Landen, Belgium; Tom Krajci, Cloudcroft, NM; Don Wells, Missouri City, TX; Pierre De Ponthiere, Lesve, Belgium, Hubert Hautecler, Boutersem, Belgium, Berto Monard, Tiegerspoort, South Africa; and Shawn Dvorak, Clermont, FL, clearly show superhumps, indicating EG Aqr is a SU UMa-type dwarf nova; data collected as the superoutburst progresses are being analyzed to determine the superhump behavior and refine the variable classification. All CCD observations reported to the AAVSO may be found on the AAVSO website (http://www.aavso.org).

AAVSO 'e' and 'f' scale charts and photometric sequence information are available at http://www.aavso.org/vsp

[obsolete http://www.aavso.org/cgi-bin/searchcharts3.pl?name=eg%20aqr ]

Visual observations and selected CCD observations reported to the AAVSO include (note that differences between visual and CCD observations are likely due to differences in comparison stars used):

OCT 28.5410, <15.6  (R. Stubbings, Tetoora Road, Victoria, Australia, RASNZ sequence);
31.1740, <16.5 CR (P. Schmeer, Bischmisheim, Germany, Univ. Iowa Rigel Telescope, Henden/Sumner sequence);
NOV 08.3260, 12.7 CR (Schmeer);
08.4480, 12.4 (Stubbings, discovery observation);
08.5320, 12.5 (Stubbings);
08.9340, 13.1 (G. Poyner, Birmingham, England, 123+132 compstars on AAVSO 2004 chart);
09.0472, 13.399 CCD (T. Krajci, Cloudcroft, NM, Comp = GSC 5822-0406
(AAVSO 11.9));
09.0496, 13.31 V (D. Wells, Missouri City, TX, GSC 5822-0406);
09.2866, 13.13 CCD (Krajci);
09.4370, 12.7 (Stubbings);
09.4650, 12.7 (Stubbings);
09.5670, 12.7 (Stubbings);
09.7257, 12.9 (W. Kriebel, Schierling/Walkenstetten, Germany);
09.7624, 12.918 CCD (P. De Ponthiere, Lesve, Belgium, GSC 5822-0406);
09.7938, 12.8 (H. Hautecler, Boutersem, Belgium);
09.8011, 13.192 CCD (De Ponthiere);
09.8020, 12.7 visual (Schmeer, 123+132 on AAVSO 2004 chart);
09.8800, 12.9 (Poyner);
10.2892, 13.182 CCD (Krajci);
10.4480, 12.9 (Stubbings);
10.4900, 12.7 (Stubbings);
10.5240, 12.7 (Stubbings);

CCD observers are asked to carry out as long CCD time series runs (V filter) as possible, with a cadence such that each observation has at least S/N=50. If observations with more than one filter are possible, all should be made within the same S/N=50 constraint. Visual observations are welcome; please observe several times during the night and at regular, frequent intervals (~10 minutes).

Please report observations to the AAVSO as 2320-08 EG AQR, and be sure to indicate the chart and comparison stars you used.

Note: Information in this Alert Notice is taken in part from postings to cvnet-alert, baavss-alert, and vsnet-alert; these sources are acknowledged with thanks.

Congratulations to Rod on his discovery of this rare event!

Thank you very much for your astronomical contributions and efforts.

Good observing!

Elizabeth O. Waagen
Senior Technical Assistant

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