Blue nova
Posted: Wed Dec 25, 2013 7:23 am
The progenitor of Nova Delphini 2013 may have been very blue indeed.
Ann
See http://www.aavso.org/photometry-progeni ... hotometric.Ulisse Munari and Arne Henden wrote:
The Asiago plate archive has been searched for old plates covering the region of the sky containing Nova Del 2013 (V339 Del). The brightness of the progenitor was measured against a deep BVRI photometric sequence that we calibrated on purpose. The mean brightness of the progenitor on Asiago plates is <B>=17.27 and <V>=17.6, for a mean color (B-V) = -0.33. The recorded total amplitude of variation in B band is 0.9 mag. Color and variability are in agreement with a progenitor dominated by the emission from an accretion disc. The progenitor was marginally detected also by the APASS all sky survey on April 2012. We have stacked the CCD images from three individual visits and measured the progenitor at B=17.33+/-0.09 and V=17.06+/-0.10 mag.
Ann