Alert Notice 379: Support for Spitzer observations of tremendous outburst amplitude dwarf novae (TOADs)

May 16, 2008 : Dr. Steve Howell (NOAO) requests monitoring of a subset of the known and suspected tremendous outburst amplitude dwarf novae (TOADs) in support of Spitzer Space Telescope observations of these objects. Observers are asked to increase their monitoring of the objects in the table below in support of this campaign.  We note that several of these objects -- notably the WZ Sge stars WZ Sge, GW Lib, and V455 And -- are not expected to superoutburst during the next year, but observations are still encouraged in case they exhibit unexpected behavior.  

The following table lists the observed magnitude range and an outburst threshold for each star. Any observation above the threshold should be  considered in outburst, and any observation at or near the maximum is  likely a superoutburst.  If the object is in outburst or near maximum, please contact the AAVSO immediately.  Spitzer observations will not be triggered immediately, however, an Alert Notice will be issued requesting concentrated coverage of the star.

Name      RA(J2000)   Dec(J2000) thrshld. maximum minimum  type  period(m)
WX Cet   01:17:04.20  -17:56:23.0  13.5     9.5    18.5    ugwz   83.9
UV Per   02:10:08.00  +57:11:20.0  15.0    11.0    17.5    ugsu   93.3
UW Per   02:12:29.59  +57:05:19.7  15.5    13.5    18.0    ug    unknown
PQ And   02:29:29.54  +40:02:40.2  15.0    10.1    19.0    ugwz  unknown
SW UMa   08:36:42.70  +53:28:38.0  15.0     9.7    16.5    su/dq  81.8
EG Cnc   08:43:04.00  +27:51:50.0  15.0    11.9    17.0    ugwz   84.6
BZ UMa   08:53:44.20  +57:48:41.0  14.5    10.2    15.9    ugsu   97.9
RZ Leo   11:37:22.2   +01:48:58.0  14.5    11.5    19.2    ugwz  109.5
QZ Vir   11:38:26.80  +03:22:07.0  13.5    10.0    15.7    ugsu   86.4
BC UMa   11:52:15.90  +49:14:42.0  15.0    10.9    18.3    ugsu   91.2
HV Vir   13:21:03.10  +01:53:30.0  15.0    11.5    19.0    ugwz   83.5
UZ Boo   14:44:01.21  +22:00:54.8  15.0    11.5    20.4    ugwz  unknown
EK TrA   15:14:00.40  -65:05:36.0  14.0    10.4    16.6    ugsu   90.5
GW Lib   15:19:55.40  -25:00:25.0  14.0     9.0    18.5    ugwz   76.8
V544 Her 16:38:05.40  +08:37:59.0  16.0    14.5    20.0    ug    unknown
DH Aql   19:26:10.8   -10:15:29.0  15.0    12.5    18.3    ugsu  unknown
KX Aql   19:33:53.70  +14:17:48.0  15.5    12.5    18.4    ug     86.9
WZ Sge   20:07:36.50  +17:42:15.0  14.0     7.0    15.5    ugwz   81.6
VY Aqr   21:12:09.2   -08:49:37.0  15.0     8.4    17.5    ugwz   91
V455 And 23:34:01.45  +39:21:41.0  14.0     8.5    16.5    ugwz   81.1

Both visual and CCD observations are useful, and multicolor photometry would be greatly appreciated.  Visual observers are asked to observe these objects as normal; if they are already in your list of objects, please continue, and if not, please add them to your nightly observing program.  CCD observers are asked to use exposure times such that you can obtain a signal-to-noise of 50 per observation.  CCD observers are asked to obtain filtered photometry, in at least two filters if you are capable of doing so; single-filtered or unfiltered observations are also appreciated. Time-series observations are not required except for cases where superhumps have not yet been observed or the orbital period is unknown, and then are only requested when the star is in outburst.  For both visual and CCD observations, "fainter-than" observations are also important, particularly for objects with faint minima, so please report them as promptly as positive detections.

This campaign begins now (May 16, 2008) and continues through May 2009. Once an object has been verified in superoutburst, Spitzer observations will be scheduled within 2-4 weeks of maximum, and will be repeated twice -- 4-6 weeks and 6-10 weeks later. Observers are asked to provide nightly monitoring of these stars, and to begin intensive observations if and when any of them go into outburst to determine whether the star is in superoutburst.

For more detailed information on this campaign, visit the following URL:

This campaign is being organized for Dr. Howell at AAVSO Headquarters by Dr. Matthew Templeton.

This AAVSO Alert Notice was compiled by Matthew Templeton.



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