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Z CamPaign Update September 27, 2010

By Mike Simonsen

It’s been a full year since the start of the Z CamPaign so I will summarize what we have found so far, point out some interesting stellar behavior, and present the revised list of Z Cam stars to follow for the next year.

I have spent the last two weekends writing the second Z Cam paper from this project. It will present the initial findings and describe the data analysis. (The first was an overview of the Z CamPaign presented at the SAS meeting in May 2010, attached on this page below)

The impostors!

Several stars in the campaign, and some others that have been suspected or claimed to be Z Cams for years have been shown not to be Z Cams from analysis of their long-term light curves.








V344 Ori- There is not enough data to say what type of star this is for sure, but its outburst cycle and outburst amplitude suggest it is a UGSU or UG. This is a rarely outbursting CV worthy of attention. It just isn’t a Z Cam.

V1363 Cyg- The CCD light curve of this star when at or near minimum is quite interesting, but it too has too long an outburst cycle and is unlikely to be UGZ, since all of the confirmed systems have outburst cycles measured in days to weeks, not months or years. This is another CV worth following. It’s just not a Z Cam.

Since these stars are not Z Cams we are dropping them from the campaign list.

MN Lac has proved to be so faint even CCD observations have been fruitless, so it is being dropped from the campaign list also.

Stars that have been shown to be bona fide Z Cams with obvious examples of standstills in the long-term light curves are:

Z Cam- the prototype system

RX And

TZ Per


AT Cnc

SY Cnc (only one standstill in April 1982)

AH Her

UZ Ser

EM Cyg (UGZ+E)

VW Vul

HX Peg

All these stars will remain on the campaign list indefinitely.

Patrick Wils has discovered a new member of the Z Cam class from CRTS light curve data- Leo5. This is also an eclipsing system so should prove to be a very interesting project star. I’ve added it to the new campaign list.

PY Per Alert!

Although we missed any recent outburst, PY Per may actually be in standstill right now around 15.5V. It is at least a full magnitude below outburst level and has remained there for some time now. Something is going on as this at least 2.5 magnitudes above quiescence.

The IW And stars

IW And and V513 Cas look like cousins or sisters. They both exhibit some sort of quasi-periodic, quasi-eclipsing light curves. They may now have another relative. V849 Her may be doing the same weird light dance. Nightly coverage is needed to begin to get a handle on this. These three stars are priority targets until further notice.

New Stars for 2010-2011

There will be several new stars added to the campaign this year.

WW Cet- probably not a UGZ, but exhibits a wide variety of behaviors below maximum light that may shed light on the Z Cam phenomena.
AY Psc- An eclipsing system that needs to be verified as Z Cam or not. Sparse data to date.

HL CMa- A Known Z Cam that could use better coverage. Challenging target due to its proximity to Sirius.

Leo5- A new Z Cam discovered by Patrick Wils.

V426 Oph- A wide variety of opinions in the literature about the nature of this star.

HS 2133+0513- A little studied Hamburg Survey CV.

The complete listing for 2010-2011 is attached below.

Mike Simonsen,
Sep 27, 2010, 5:08 PM
Mike Simonsen,
Sep 27, 2010, 5:08 PM
Mike Simonsen,
Sep 27, 2010, 5:08 PM