V570 Per: Characterization of a Benchmark Eclipsing Binary

TL;DR

This work presents a comprehensive, multi-technique analysis of the detached eclipsing binary V570 Per, combining 35 high-resolution spectra with five years of TESS photometry to derive precise fundamental parameters and detailed chemical abundances for both F-type components. Spectral disentangling with FD3 enables independent Teff and abundance determinations via SP_Ace, while PHOEBE jointly fits RVs and light curves to yield masses, radii, and orbital geometry with negligible eccentricity. Evolutionary modeling with MESA, allowing variations in helium and mixing length, places the system at t ≈ 577 ± 60 Myr and predicts mass-transfer initiation for the primary in ≈ 2.82 Gyr. Kinematic and orbital analyses place V570 Per in the Galactic thin disk with a birth radius around 7.6–7.8 kpc, and a possible origin in a metal-rich inner-disk environment, such as Melotte 25, though a definitive cluster association remains open. The Ca abundance anomaly between the two stars is robust and provides a notable chemical constraint on their common origin and evolution.

Abstract

This study presents a comprehensive analysis of the detached binary system V570\,Per through combined photometric, spectroscopic, and astrometric observations. By disentangling the composite spectra, precise fundamental parameters and detailed chemical abundances were determined for both stars. The primary component has a mass of $1.4569_{-0.0100}^{+0.0094}$ $M_{\odot}$, a radius of $1.543_{-0.009}^{+0.012}$ $R_{\odot}$, an effective temperature of $6556_{-26}^{+64}$ K, and a metallicity of $+0.18_{-0.01}^{+0.03}$ dex, while the secondary has a mass of $1.3579_{-0.0089}^{+0.0094}$ $M_{\odot}$, a radius of $1.377_{-0.015}^{+0.013}$ $R_{\odot}$, an effective temperature of $6468_{-21}^{+32}$ K, and a metallicity of $+0.15_{-0.01}^{+0.02}$ dex. The system is estimated to be $577_{-60}^{+60}$ Myr old with a synchronized orbit. The available O-C data imply a minimum mass of 0.57 $M_{\odot}$ or 0.11 $M_{\odot}$ for the third body, corresponding to eccentric and circular orbits, respectively. \texttt{MESA} evolutionary models indicate that the primary will fill its Roche lobe and begin mass transfer to the secondary in about 2.8 Gyr, whereas the secondary will reach the terminal-age main sequence in approximately 3.2 Gyr. The chemical composition of both stars shows remarkable consistency, confirming their common origin, except for calcium, which is significantly enhanced in the primary. Line measurements support this difference and are therefore interpreted as an intrinsic abundance variation rather than an artifact of the analysis. The overall solar-rich metallicity, combined with a relatively low $α$-element content, links V570\,Per to the Galactic thin-disk population. In addition, Galactic orbit analyses of open clusters in the solar neighborhood have revealed that the V570\,Per system may have originated from the Melotte 25 open cluster.

Figures (17)

• Figure 1: Available photometric TESS data for V570 Per including exposure times for each sector.
• Figure 2: Observed RVs with best-fitting radial velocity curves, and photometric data with LC modelling. Filled and empty circles represent the RVs of the primary and the secondary components of V570 Per, respectively. In the RV panel, the red and blue dots represent the Tomasella2008 and ELODIE data, respectively. In the LC panel, the dark green dots represent the TESS data, while the black curve is based on the best-fitting LC model for this photometric data set.
• Figure 3: A corner plot of the posteriors for the fundamental parameters of V570 Per.
• Figure 4: The spectra of the individual components were obtained through spectral disentangling and are shown alongside the observed composite spectrum.
• Figure 5: Upper panel shows the disentangled spectra of both components with SP_Ace models and their residuals, while the lower panel presents a selected region from the primary component, highlighting the spectral lines used for chemical abundance analysis.