THE LOW-MASS INTERACTING BINARY SYSTEM OO Aql REVISITED: A NEW QUADRUPLE SYSTEM
In this study we present photometric and spectroscopic variation analysis and an orbital period study of a low-mass interacting system OO Aql. Simultaneous solution of the light and radial velocity curves provides us with the determination of a new set of stellar physical parameters for the primary and the secondary companion, M{sub 1} = 1.05(2) M{sub Sun }, M{sub 2} = 0.89(2) M{sub Sun }, R{sub 1} = 1.38(2) R{sub Sun }, R{sub 2} = 1.28(2) R{sub Sun }, log (L{sub 1}/L{sub Sun }) = 0.258, and log (L{sub 2}/L{sub Sun }) = 0.117, and the separation of the components was determined to be a = 3.333(16) R{sub Sun }. Newly obtained parameters yield the distance of the system as 136(8) pc. Analyses of the mid-eclipse times indicate a period increase of (P/ P-dot )=4 Multiplication-Sign 10{sup 7} yr that can be interpreted in terms of the mass transfer (dM/dt) = 5 Multiplication-Sign 10{sup -8} M{sub Sun} yr{sup -1} from the less massive component to the more massive component. Our new solution confirmed that OO Aql is a multiple system in the form of AB + C + D. We found initial astrophysical parameters for the component of the system and its current age to be 8.6 Gyr using a non-conservative stellar evolution model (EV-TWIN code).