2017ApJ...834...99M

KIC 7177553 is a quadruple system containing two binaries of orbital periods 16.5 and 18 days. All components have comparable masses and are slowly rotating with spectral types of ∼G2V. The longer period binary is eclipsing with component masses and radii M₁ = 1.043 ± 0.014 M_☉, R₁ = 0.940 ± 0.005 R_☉ and M₂ = 0.986 ± 0.015 M_☉, R₂ = 0.941 ± 0.005 R_☉. The essentially equal radii measurements are inconsistent with the two stars being on the man sequence at the same age using standard nonmagnetic stellar evolution models. Instead a consistent scenario is found if the stars are in their pre-main-sequence phase of evolution and have an age of 32-36 Myr. We have also computed evolutionary models of magnetic stars, but we find that our nonmagnetic models fit the empirical radii and effective temperatures better than the magnetic models.