Absolute parameters of the Algol binary V505 Sgr from infrared JK light curves

Abstract

We present the first light curves of V505 Sgr in the infrared (IR) J and K bands. The light curves are analysed with a code based on Roche geometry and stellar model atmosphere fluxes in order to determine a new set of stellar and orbital parameters. From the visual-IR photometry we find no evidence of IR excess in the system. We study the effect of the non-synchronous rotation of the primary star in the light and radial velocity curves. The distance of the system is estimated as 112 +/- 4pc, in close agreement with the Hipparcos parallax.