EDP Sciences
Free access
Volume 497, Number 2, April II 2009
Page(s) 481 - 485
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361/200810512
Published online 05 March 2009
A&A 497, 481-485 (2009)
DOI: 10.1051/0004-6361/200810512

Research Note

Five colour photometry of the RRd star V372 Serpentis

J. M. Benkő and S. Barcza

Konkoly Observatory of the Hungarian Academy of Sciences, PO Box 67, 1525 Budapest, Hungary
    e-mail: [benko;barcza]@konkoly.hu

Received 3 July 2008 / Accepted 30 January 2009

Aims. The first U-band and new $BV(RI)_{\rm C}$ photometry of the RRd star V372 Ser is presented to determine some parameters of the star.
Methods. In April, May 2007, 2812 $U,B,V,R_{\rm C},I_{\rm C}$ frames were obtained at Konkoly and Teide Observatories and 1508 V observations were collected from the literature. Fourier fitted light curves were derived in all bands.
Results. The non-linearly coupled frequencies $f_0=(2.121840\pm .000001)~\mbox{cycles~day$^{-1}$ }$, $f_1=(2.851188\pm .000001)~\mbox{c~d$^{-1}$ }$, i.e. periods $P_0=0.4712891\pm .0000002$ days, $P_1=0.3507310\pm .0000001$ d, P1/P0=0.7441950, amplitudes A0(V)=0.15399 mag, A1(V)=0.20591 mag, and phases have been found. $A_1/A_0=1.319\pm .008$ 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.

Key words: stars: variables: RR Lyr -- stars: fundamental parameters -- stars: individual: V372 Serpentis

© ESO 2009