Superoutburst of DM Lyr

(vsnet-alert 455, Gary Poyner)

Dear Colleagues,

Outburst of DM Lyr (needs confirmation), which is monitored as part of the TA/BAAVSS Recurrent Objects Programme.

Jly 05.9771 UT    mv=<14.8     Poyner  40cm
    07.0431           14.5        "
    07.0611           14.4        "
    07.0819           14.3        "

My records show that the last outburst occurred on November 20 1995, when Jochen Pietz observed it at mag. 14.2

Has any recent photometry been done on comparison stars for DM Lyr?

Gary Poyner

Outburst CCD image

1996 July 12, 25-cm SCT + ST-7 unfiltered, 60s exposure (by T. Kato and D. Nogami)

previous VSNET observations
link to AAVSO NEWS FLASH No. 35 (AAVSO web)

Discovery of superhumps

(vsnet-alert 409, D. Nogami)

Dear Colleagues,

We, Ouda Team, observed DM Lyr last night (7/16) and detected superhumps with an amplitude of about 0.1 mag. DM Lyr has, thus, been proved to be a new member of SU UMa stars! Our preliminary period analysis gives 0.066 (+-0.002) day as the best estimated superhump period. The future behavior of this variable also deserves attention.

We thank all observers who have posted their observations of DM Lyr to VSNET!!!

Best regards,
Daisaku Nogami

Comment and observation by T. Vanmunster

(vsnet-obs 3151)

Dear colleagues,

At 16:48 17/07/96 +0100, Gary Poyner wrote:
>Lyr DM         16.967          14.6  Could this have possibly been a 
>                                     superoutburst? 

Comparing the present outburst with photometric summaries of previous ones, one indeed gets the impression that the current outburst must be a superoutburst (hence establishing DM Lyr as a member of the UGSU dwarf novae). I have started a time series CCD photometry on DM Lyr last night (for about 3 hours), to find out if any superhumps are detectable. I haven't reduced the CCD images yet, but let you know my findings. Has anyone else attempted CCD photometry on this object ? Or does anyone know about published photometric results ?

Tonny Vanmunster
CBA Belgium

(vsnet-obs 3153)

Dear Colleagues,

The DM Lyr CCD photometry, obtained last night (July 16/17) at the CBA Belgium (unfiltered 90s exposures using a 25-cm SCT with ST-7 CCD) clearly shows the existence of superhumps in this system (hence proving the SU UMa nature). A very preliminary analysis of the superhump period yields a best value of 0.067d +/- 0.001d (PDM method) and a mean amplitude of 0.08 mag. These values correspond very well with the results obtained independently by the Ouda team of Kyoto University, Japan.

At the moment of this writing, the telescope is performing another CCD photometry run on DM Lyrae (July 17/18).

Best regards,
Tonny Vanmunster
CBA Belgium

Comment by E. Broens

VSNET chart

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