Absolute properties of the main-sequence eclipsing binary FM Leo

Abstract

First spectroscopic and new photometric observations of the eclipsing binary FM Leo are presented. The main aims were to determine orbital and stellar parameters of two components and their evolutionary stage. First spectroscopic observations of the system were obtained with DDO and PST spectrographs. The results of the orbital solution from radial velocity curves are combined with those derived from the light-curve analysis (ASAS-3 photometry and supplementary observations of eclipses with 1 m and 0.35 m telescopes) to derive orbital and stellar parameters. JKTEBOP, Wilson-Devinney binary modelling codes and a two-dimensional cross-correlation (TODCOR) method were applied for the analysis. We find the masses to be M_1 = 1.318 $\pm$ 0.007 and M_2 = 1.287 $\pm$ 0.007 M_sun, the radii to be R_1 = 1.648 $\pm$ 0.043 and R_2 = 1.511 $\pm$ 0.049 R_sun for primary and secondary stars, respectively. The evolutionary stage of the system is briefly discussed by comparing physical parameters with current stellar evolution models. We find the components are located at the main sequence, with an age of about 3 Gyr.Comment: 5 pages, 4 figures, to appear in MNRA

The surface brightness–colour relations based on eclipsing binary stars and calibrated withGaiaEDR3

“…Our photometric parameters are consistent to within 2σ with the parameters found by Maxted & Hutcheon (2018) who solved the long-cadence K2 data. A comparison with physical parameters reported by Ratajczak et al (2010) shows remarkably good agreement, although our parameters are an order of magnitude more precise. The masses reported by Sybilski et al (2018) are consistent with our values to within 2σ, while the radii reported by them are very different.…”

“…Here we present the full analysis of those two systems with updated physical parameters. An analysis of light-and radial velocity curves of FM Leo was published by Ratajczak et al (2010), who derived the fundamental physical parameters of the system. Updated mass measurements of the components, together with the analysis of the Rossiter-McLaughlin effect, were provided by Sybilski et al (2018).…”

“…To represent the Kepler band within the WD code we used the Cousins R band (filter 15 in the WD code) which has very similar effective wavelength. For our initial solution we used parameters from Ratajczak et al (2010). We quickly found that a circular orbit produces small systematic trends in the residuals during both eclipses, so we set the eccentricity and the longitude of periastron as free parameters during the fitting.…”

Tracking spin-axis orbital alignment in selected binary systems: the Torun Rossiter–McLaughlin effect survey

“…The eclipsing ephemeris of the system was first derived in Solonovich et al (2003) from their photometric data, however, the period found was 3.3643328 days that is approximately half of the currently derived period (e.g. the 6.728606 days of Ratajczak et al 2010). The absolute properties of FM Leo were studied in Ratajczak et al (2010) where the combination of photometric and spectroscopic measurements allowed for the derivation of orbital and physical parameters.…”

Discovery and characterisation of long-period eclipsing binary stars from Kepler K2 campaigns 1, 2, and 3

“…3.1.8. EPIC 201488365 = FM Leo Ratajczak et al (2010) have published spectroscopic orbits for both components of FM Leo together with an analysis of the light curves available to them at that time. We have used the semi-amplitudes K 1 and K 2 from Ratajczak et al together with the parameters from our analysis of the Kepler K2 light curves with jktabsdim 4 to derive the absolute parameters for FM Leo given in Table 6.…”