New SU UMa-type dwarf nova V701 Tau

In CVC 75 (vsnet-obs 1766), T. Vanmunster reports on his detection of an outburst of V701 Tau, probably first ever since discovery. Available observations (taken from CVC 75):


The Ouda team has just confirmed this outburst using a 60-cm telescope + CCD, giving a rough magnitude estimate of V~14.3. Observers should note that the object is slightly mis-identified on the atlas by Downes & Shara (1993). The true object is located ~30 arcsec ESE to the position given in their catalog -- making a regular triangle with nearby GSC 14.3 & 14.8 stars. This identification has been confirmed by checking the discovery report by Esastova, L.K. 1973, Astron. Tsirk. 774, which also gives the following magnitude estimates for the 1970 outburst ( more info.)

Preoutburst image taken on Nov. 21, on which a rough position of the object is marked.


Preliminary anysis of CCD frames taken at Ouda Station (Kyoto Uni- versity) gives the following astrometry of V701 Tau.

03h 44m 01s.91 +21o 57' 07".2 (J2000.0) 4 GSC stars

Outburst images

CCD image by Makoto Iida

CCD image taken at Ouda Station

VSNET charts

in PostScript

in VSNET format

Detection of superhumps

(vsnet-alert 302)

Dear Colleagues,

V-band time-resolved CCD observations of V701 Tau (Dec. 27.446 -- 27.706 UT) finally revealed a development of superhumps in V701 Tau. Superhumps were still small in amplitude (~0.05-0.06 mag), but are clearly present and are likely to be just growing. A preliminary analysis gives the best period of 0.073 day. The present observations has thus firmly established the SU UMa-type nature of this dwarf nova.

Congratulations to Tonny Vanmunster on his visual discovery of an outburst of this faint dwarf nova, and we would like to express sincere thanks for his and his colleagues' nightly efforts in monitoring such faint objects and prompt notification; without either of them, the early develop- ment of superhumps (or even the outburst) would have been easily missed.


Taichi Kato & Ouda team

CCD photometry of V701 Tau at Ouda Station on Dec. 29 clearly shows fully grown superhump with an amplitude of 0.25 in V. A preliminary analysis yielded a superhump period of P=0.069 day, which is significantly shorter than one obtained in early stages of superhump development.



Taichi Kato & Ouda team

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