The discovery of the photometric variability of a new SR-type variable star in the M31 galaxy, while searching for variable red sources using V and I observations from the Galati Astronomical Observatory
ATel #14368; J. O. Tercu (Galati Astronomical Observatory - C73), G. C. Neagu (Galati Astronomical Observatory - C73)
on 4 Feb 2021; 23:21 UT
Credential Certification: Elias Aydi (eaydi@saao.ac.za)
Subjects: Optical, Star, Variables
We report the discovery of a new SR-type variable star located in the M31 galaxy. We cross-identify it as 2MASS J00405619+4045461 = Gaia EDR3 381154123908000512 = [M31] Galati V23. Gaia EDR3 381154123908000512 has J2000 coordinates R.A. = 00h40m56.206s Decl. = +40d45m46.173s, r = 19.75 from ZTF DR4. The range is 19.4-20.1 r. The time of maxima is 2458228 HJD. During the RSG search in M31 using the 0.4 m Ritchey-Chretien telescope with SBIG STL-6303E CCD camera using 10 exposures of 120s in V and I filters, we observed a very high V-I difference. Gaia EDR3 BP-RP = 3.08, suggesting a very red star, confirming our observations. We analyzed the ZTF DR4 and PS1 data in search of variability using Peranso 3 (CLEANest algorithm) and identified a 824 +\- 5 d period. J-K = 1.67 (2MASS), W3-W4 = 2.63 (WISE). The data was posted on the NGCA variable star catalog's extragalactic findings page.
