DO Vul : likely a new UGSU-type dwarf nova

On November 7th, 2005, Patrick Schmeer announced the detection of a long outburst of the dwarf nova DO Vul, based on CCD observations obtained by the Rigel Telescope of the University of Iowa. Based on his analysis, DO Vul was first seen at mag 15.3CR on Nov 2nd, 2005, and then gradually started to fade, reaching mag 15.9CR by Nov 7th.

Following Patrick's announcement, I started an unfiltered CCD photometry session on this target (2005, Nov 08/09). The session lasted for 3.2h, under transparent skies. I used a 0.35-m f/6.3 telescope and ST-7XME CCD. The resulting light curve shows DO Vul at an average (unfiltered) magnitude of 16.9, dropping by 0.22 mag over the course of the session.

DO Vul (unfiltered) light curve of 2005, Nov 08/09

A superhump-like modulation with an amplitude of 0.2 mag is visible in the light curve. Using Peranso's ANOVA method, I find a best period of 0.065 +/- 0.006d. PDM, Lomb-Scargle and other methods yield similar values. A Fisher Randomization method, which calculates the false alarm probability of the quoted period, yields a very high significance for the period.

Based on the above, the likelihood of DO Vul being an SU UMa-type dwarf nova is considerable, but more observations are required to confirm these findings. Unfortunately, the present outburst seems to be nearing its end.

ANOVA period analysis on DO Vul

Phase diagram resulting from folding a period of 0.065d






Copyright © 2005 - Tonny Vanmunster.