We are now in the seventh year of the Z CamPaign. I want to thank all the CCD and visual observers who have contributed to this campaign since 2009. With your help we have met all the original science goals, published several papers, identified new Z Cams, unearthed a poorly understood group of anomalous Z Cams and whittled down the list of Z Cam suspects and impostors.
I'm happy to report, there is still plenty to do.
All the bona fide Z Cams should be observed every night. They still have surprises in store for us and now that we have classified them unambiguously we need to maintain a historical record of their unique and interesting behavior. The gold is buried in the long-term light curves of these stars. So if you adopt them into your program, consider it a multi-year, or lifetime, commitment.
There are plenty of bright Z Cams that visual observers can follow throughout their range of variability. CCD observers should concentrate on Z Cams that get fainter than 15.0V, especially the handful of challenging faint targets mentioned later in this update.
The Z Cam List website lists all the bona fide and suspected Z Cams.
New Discoveries
In the February 2015 Z CamPaign Update I asked observers to concentrate on a new Z Cam candidate, 1RXS J062954.6-033520 (J0629). Fortunately, patience and persistence has paid off. I am making the call on this one as a new bona fide Z Cam system. As you can see in the light curve below, J0629 was in standstill coming out of the seasonal gap, hovering between 13.0 and 13.2V. The standstill lasted through the month of August 2015, and then J0629 went into outburst from standstill at the end of September. A paper is in preparation.
(click on any light curve to enlarge)
Almost all the CCD data in this light curve are from Josch Hambsch, but this is a great star for everyone to follow. It ranges from 12.3 - 14.5V, so it’s observable visually in a 10” telescope throughout its range, and at -3 degrees declination it is observable from both northern and southern observatories.
UY Pup: Déjà vu
In February of 2014 Rod Stubbings wrote to me telling me he had discovered a new Z Cam star hiding in the dwarf novae weeds, OQ Car. I wrote about his discovery here. This year Rod wrote to me with an almost identical story. This time the subject was UY Pup. Rod has been following this star for years and had become familiar with its normal dwarf nova pattern of outburst and quiescence.
After an outburst in the end of December 2015 UY Pup had failed to return to quiescence and by the time he wrote me in February UY Pup looked like it was stuck in the low to mid 14th magnitude range, right where I would expect to see a standstill occur in a dwarf nova that ranges from 13.0 to 16.1.
I immediately got it on the observing queues for AAVSOnet and enlisted a few friends to begin nightly monitoring of it with their CCDs. As luck would have it, UY Pup dropped out of standstill almost as soon as we began collecting CCD data, but Rod’s visual data look like they will be enough to write another discovery paper.
After the first historic standstill of OQ Car, that system went into a very active phase with several unambiguous standstills occurring since mid 2014. Those have all been well observed with visual and CCD data. With any luck, UY Pup will reward us with more confirmation in the coming months now that we have trained a bunch of telescopes and observers on her.
