Analysis of photometric and spectroscopic observations of classical nova V615 Vul

We present an investigation of the classical nova V615 Vul that erupted on July 29, 2024. The results obtained are based on our multicolor observations at AI SAS, the M. R. Štefánik Observatory in Hlohovec and MAO NASU, as well as photometry from the AAVSO and ASAS-SN database. We also present spectral observations obtained with the 1.3-meter telescope at Skalnaté Pleso Observatory, when the very broad asymmetric H α emission line dominated during the nova’s decline. From the constructed light curves, we determined the brightness decay rates at 2 and 3 magnitudes, obtaining t2,V = 5ᵈ t 2 , V = 5 d .2, t3,V = 8ᵈ t 3 , V = 8 d .9 and t3,B = 11ᵈ t 3 , B = 11 d .6, which corresponds to very fast novae. The light curve shows a variation with a period of 6.5 days from day 12 to about day 90 after the outburst maximum. We also detected and analyzed short-term variations in V V , Rc R c and Ic I c starting around day 35. We suppose that the found oscillation of 0 d .2238 ± 0.005 is the orbital period of V615 Vul. We calculated color indices and estimated the color temperature of the system. The tracks in the V-Rc V − R c and Rc-Ic R c − I c diagrams exhibit loop-like variations caused by the broad H α emission line, while the tracks in $U-B$ U − B / $B-V$ B − V diagram reflect changes in color temperature during the outburst - behavior typical of many cataclysmic variables and novae. We also estimated the main parameters of the system, such as the absolute magnitude, distance, extinction, and mass of the white dwarf.