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WZ Sge

One of the CV variable stars which has recently gone into outburst is WZ Sge.  This star is thought to have outbursts every 22 years but recently it is thought that the cycle may actually be every 11 years.  2001 seems to be one of those years.  The star field is shown below:
wzsge.jpg (41018 bytes) 

Royko, Uemura, Matsumoto, et.al. published "First Detection of the Growing Humps at the Rapidly Rising Stage of Dwarf Novae AL Com and WZ Sge" on Oct. 29, 2001.  A copy in Adobe PDF format can be downloaded here:

 

"The 2001 Superoutburst of WZ Sagittae", Joseph Patterson, Gianluca Masi, Michael Richmond, Brian Martin, Edward Beshore, David Skillman, Jonathan Kemp, Tonny Vanmunster, Robert Rea, William Allen, Stacey Davis, Tracy Davis, Arne Henden, Donn Starkey, Jerry Foote, Arto Oksanen, Lewis Cook, Robert Fried, Dieter Husar, Rudolf Novák, Tut Campbell, Jeff Robertson, Thomas Krajci, Elena Pavlenko, Panos Niarchos, Orville Brettman, and Stan Walker.   Publications of the Astronomical Society of the Pacific.  (in press, to appear July 2002)  Download here:

 

This graph shows my cumulative photometry of WZ Sge from July 26 to Sept 4, 2001.  The first few observations were unfiltered and the balance were "V" band filtered.
WZ Sge Cumulative Photometry.gif (7045 bytes)

I made an unfiltered photometry run on WZ Sge on July 26, 2001.  The data is composed of 289 separate 2.5 second images.  Plotting the change in magnitude in comparison to a nearby star GSC 1621:1830 gives the following graphs:
WZSge Photometry Graph.jpg (135915 bytes)

Another similar unfiltered photometry run was made on July 29th.  This run is composed of 360 separate 14 second images under similar conditions.  The graph of this data is shown below:
WS Sge graph for Jul29_01.gif (13008 bytes)

This unfiltered photometry run was for July 30.   There is a hole in the data near the end of the run due to clouds.  The eclipses are becoming very obvious and the star is rising in magnitude. 
WZ Sge July 30.gif (8418 bytes)

This next run is from July 31 and is in the V Band.  Unfortunately, there are several holes in the data where my chip saturated on the comparison star.
WZ Sge July 31.gif (8668 bytes)

This is the "V" band photometry run from August 3.  It is one of the best runs for data continuity .
WZ Sge Aug 03.gif (10569 bytes)

Article Submitted to IAU Circular by Taichi Kato

WZ SAGITTAE

T. Kato, H. Ohashi, R. Ishioka, M. Uemura, K. Matsumoto, Kyoto
University; G. Masi, Ceccano, Italy; D. Starkey, Auburn, Indiana;
J. Pietz, Erftstadt, Germany; Brian Martin, King's University College,
Alberta, Canada, on behalf of the VSNET collaboration team, report:
"Our time-resolved CCD photometry revealed that WZ Sge started to show a
different type of prominent modulations (amplitude 0.10 mag) on August
4.53 UT. The oscillations had an initial period of 0.057143 +/- 0.000046 d
between August 4.44 and 5.08 UT, which is 0.8% longer than the orbital
period (0.05669 d). Earlier observations starting on August 4.163 also
showed an suggestion of the growing signal. Later observations between
August 5.194 and 6.074 UT have shown further development of superhumps
up to 0.23 mag, and gives a mean period of 0.058884 +/- 0.000027 d.
The sharply defined profile and the period excess qualify the present
variations as genuine superhumps. The 12-d delay of superhump evolution
since the start of the outburst is the longest measured one among all
known SU UMa-type dwarf novae. The observed delay is consistent with the
earliest time of detection of a similar, but less distinct, signal during
the 1978 outburst (Heiser and Henry, IBVS 1559)."

The graph below is the data run from August 4th on WZ Sge.  "V" band photometry
WZSge Photometry Aug04.jpg (90263 bytes)

This is the August 5th run on WZ Sge.  Superhumps are evident. "V" band photometry.
WZSge Photometry Aug05.jpg (105682 bytes)

The following graph is the August 6th "V" band photometry run on WZ Sge.  The waveform is changing very fast.
WZ Sge Photometry July 06.gif (8642 bytes)

The graph below is "V" band photometry for August 7th.
WZ Sge Photometry August 07.gif (8320 bytes)

The graph below is "V" band photometry for August 10th.
WZ Sge August 10.gif (8531 bytes)

The graph below is "V" band photometry for August 12th.
WZ Sge Aug 12 2001 Image.gif (9058 bytes)

The graph below is "V" band photometry for August 13th.
WZ Sge Aug 13 2001 Image.gif (7797 bytes)

The graph below is "V" band photometry for August 14th.
WZ Sge Aug 14 2001 Image.gif (8732 bytes)

The graph below is "V" band photometry for August 17th.  Clouds came in early.  Only about an hour of photometry.  You can see that the brightness of the star is dropping rapidly.
WZ Sge Photometry for Aug 17 2001.gif (5685 bytes)

The graph below is "V" band photometry for August 20th.  The brightness of the star is increasing very rapidly, about 1.5 mag/day.  You can see humps with an amplitude of 0.15mag on the rising trend. Eclipses are also seen on the top of the humps.
WZ Sgw Photometry for Aug20_01.gif (7819 bytes)

The graph below is "V" band photometry for August 23rd.  The magnitude is still brightening.  There is a gap in the sequence due to clouds in the area.
WZ Sge Photometry Aug23 2001.gif (7068 bytes)

The graph below is "V" band photometry for August 24th.  The trend appears to be toward a reduction in the brightness.  There is a large error rate in the data due to high humidity, clouds and ground fog during the observations.
WZ Sge Photometry Aug 24 2001.gif (7461 bytes)

The graph below is "V" band photometry for August 26th.  The trend again appears to be toward a reduction in the brightness.
WZ Sge Photometry August 26 2001.gif (7613 bytes)

The graph below is "V" band photometry for August 28th.  The trend again appears to be toward a reduction in the brightness.
WZ Sge Photometry August 28 2001.gif (7015 bytes)

The graph below is "V" band photometry for August 29th.  The trend appears to be toward an increase in brightness until about JD 151.65  when the magnitude seems to level off.
WZ Sge V Band Photometry Aug 29 2001.gif (6438 bytes)

The graph below is "V" band photometry for August 31st.  The trend appears to be flat with complex maxima.
WZ Sge Photometry August 31 2001.gif (8053 bytes)

The graph below is "V" band photometry for Sept. 4th.  The trend appears to be toward a decrease in brightness now.  This has been the 7th brightening for CV.
WZ Sge Photometry Sep04 01.gif (6601 bytes)

The graph below is "V" band photometry for Sept. 5th.  The curve shows good resolution between the humps and eclipses.  The magnitude during the run is fairly flat.  Photometric error on the last half of this graph in on the order of 0.02 - 0.04!
WZ Sge Photometry Sep 5 2001.gif (7266 bytes)

The graph below is "V" band photometry for Sept 6th.  The curve shows improved photometry since the installation of a new RA and Dec Drive system on the scope mount.  This data very clearly shows the magnitude change from dimming to rebrightening.
WZ Sge Photometry Sep 06 01.gif (7238 bytes)

The graph below is "V" band photometry for Sept 12th.   A rebrightening is shown along with a few hump structures.
WZ Sge Photometry Sep 12 01.gif (5685 bytes)

The graph below is "V" band photometry for Sept 13th.  WZ is in a fairly steep decline, now.  There is a gap in the middle of the data stream for drive adjustments.
WZ Sge Photometry.jpg (85798 bytes)

The graph below is "V" band photometry for Sept 15th.   The star is now in steady state but shows a very slight increase in magnitude when the observations are grouped from other observers.
WZ Sge Photometry Sept 15 2001.gif (5437 bytes)