Fundamental Parameters of the Eclipsing Binary DD CMa and Evidence for Mass Exchange

Abstract We present a detailed photometric and spectroscopic analysis of DD CMa, based on published survey photometry new data. find an improved orbital period P o = 2.0084530(6) days. Our spectra reveal H β α absorptions with weak emission shoulders, we also color excess in the Wide-field Infrared Survey Explorer multiband photometry, interpreted as signatures circumstellar matter. model V -band light curve derived from ASAS ASAS-SN surveys, assuming semidetached configuration using mass ratio temperature hotter star our analysis. indicates that system consists B2.5 dwarf B9 giant radii 3.2 3.7 R ⊙ , respectively, orbiting circular orbit radius 6.75 . found M c 1.7 ± 0.1 T 11,350 100 K, h 6.4 20,000 500 for cooler star, respectively. broad single peaks after subtracting synthetic stellar spectra. results are consistent exchange between stars suggest existence stream gas being accreted onto early B-type star.