BRV light curve of XO-3

By modeling our newly collected measurements together with archival photometric and Doppler velocimetric data, we confirmed the unusual configuration of the XO-3 system, which contains a massive planet (M_P_=11.92_-0.63_^+0.59^M_J_) on a relatively eccentric (e=0.2853_-0.0026_^+0.0027^) and short-period (3.19152{+/-}0.00145day) orbit around a massive star (M*=1.219_-0.095_^+0.090^M{odot}).

Furthermore, we find no strong evidence for a temporal change of either vsini* (and by extension, the stellar spin vector of XO-3), or the transit profile (and thus orbital angular momentum vector of XO-3b). We conclude that the discrepancy in previous Rossiter-McLaughlin measurements (70.0{deg}{+/-}15.0{deg}; Hebrard et al. 2008; 37.3{deg}{+/-}3.7{deg}; Winn et al. 2009; 37.3{deg}{+/-}3.0{deg}; Hirano et al. 2011) may have stemmed from systematic noise sources.