Five colour photometry of the RRd star V372 Ser

TL;DR

This study presents detailed multi-band photometry and frequency analysis of the RRd star V372 Ser, determining its pulsation parameters, mode dominance, and placing it among similar stars in globular clusters.

Contribution

First UBV(RI)_C time series photometry and Fourier analysis of V372 Ser, providing detailed pulsation parameters and stellar characteristics.

Findings

Identified fundamental and first overtone frequencies with precise values.

Confirmed the first overtone as the dominant pulsation mode.

Estimated stellar parameters consistent with RRd stars in globular clusters.

Abstract

The first UBV(RI)_C time series photometry of the RRd star V372 Ser is presented to determine some parameters of the star. In April, May 2007 2812 U, B, V, R_C, I_C frames were obtained at Konkoly and Teide Observatories, 1508 V observations were collected from the literature. Fourier fitted light curves have been derived in all bands. The non-linearly coupled frequencies f_0=(2.121840+/-.000001) c/day, f_1=(2.851188+/-.000001) c/d, i.e. periods P_0=0.4712891+/-.0000002 days, P_1=0.3507310+/-.0000001 d, P_1/P_0=0.7441950, amplitudes A_0(V)=0.15399 mag, A_1(V)=0.20591 mag, and phases have been found. A_1/A_0=1.319+/-.008 has been found from averaging the amplitude ratio in the different bands i.e. the first overtone is the dominant pulsation mode. From the V observations upper limits are given for secular change of the Fourier parameters. The period ratio and period put V372 Ser among the RRd stars of the globular clusters M3 and IC 4499, mass, luminosity, and metallicity estimates are given.