The Light Curve and Period of MT696

Volume 42 number 1 (2014)

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Steven P. Souza

Department of Astronomy, Williams College, Williamstown, MA 01267; ssouza@williams.edu

Gillian Beltz-Mohrmann

Department of Astronomy, Wellesley College, Wellesley, MA 02418; gbeltzmo@wellesley.edu

Mona Sami

Department of Astronomy, Williams College, Williamstown, MA 01267; Mona.Sami@williams.edu

Abstract

We have obtained four-year narrowband light curves at 645 nm and 656 nm of the massive eclipsing binary star #696 in the Massey and Thompson (1991) study of massive stars in the Cygnus OB2 association. MT696 is a near-contact binary with components of near-equal temperature. We refine its orbital period to 1.46919 ± 0.00006 days. There is no convincing evidence of a change in period, and the 645-nm and 656-nm light curves are indistinguishable.