Differential asteroseismic study of seismic twins observed by CoRoT Comparison of HD 175272 with HD 181420

Context. The CoRoT short asteroseismic runs give us the opportunity to observe a large variety of late-type stars through their solarlike oscillations. We report the observation and modeling of the F5V star HD175272. Aims. Our aim is to define a method for extracting as much information as possible from a noisy oscillation spectrum. Methods. We followed a differential approach that consists of using a well-known star as a reference to characterize another star. We used classical tools such as the envelope autocorrelation function to derive the global seismic parameters of the star. We compared HD175272 with HD181420 through a linear approach, because they appear to be asteroseismic twins. Results. The comparison with the reference star enables us to substantially enhance the scientific output for HD175272. First, we determined its global characteristics through a detailed seismic analysis of HD181420. Second, with our differential approach, we measured the difference of mass, radius and age between HD175272 and HD181420. Conclusions. We have developed a general method able to derive asteroseismic constraints on a star even in case of low-quality data. This method can be applied to stars with interesting properties but low signal-to-noise ratio oscillation spectrum, such as stars hosting an exoplanet or members of a binary system.