PNV J00423060+4120497 is a Red LPV
ATel #6359; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic)
on 1 Aug 2014; 19:58 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient, Variables
Information about a discovery of possible nova in M31 by the Lick Observatory Supernova Search (LOSS) was recently posted here.
The object is visible on many images obtained during last decade in the course of my survey of M31 and known to me as an LPV star. I observed the object again on July 31.929 and 31.931 UT in R-band and I-band, respectively with the 0.65-m telescope at Ondrejov. The following magnitudes were obtained:
2014 Jul. 31.929 UT, R = 19.1 ± 0.25; 31.931, I = 17.1 ± 0.15.
The significantly red color of the object is not typical for a classical nova unless it is highly reddened, which is not expected in the line of sight to the object. The object is more likely a red LPV. This classification is strongly supported by the presence of the object on many archival images as well as in the Survey of Local Group Galaxies Currently Forming Stars: I. UBVRI Photometry of Stars in M31 and M33 by Massey et al. (2006, AJ, 131, 2478) where is designated as J004230.55+412049.1 having the following V, (B-V), (V-R), and (R-I) magnitudes, respectively: 22.603 ± 0.087, 0.601 ± 0.182, 0.822 ± 0.115, 1.549 ± 0.074. Since Massey's magnitudes are averages of different numbers of measurements obtained in different epochs in each band, they are influenced by the variability of the object.
A comparison of archival Massey's I-band and R-band images taken at different epochs clearly shows large amplitude of brightness changes of the object as well as its significantly red color and is available through the link below.
Comparison image
