The disk of material around AFGL 4176 is estimated to have a radius of roughly 2000 AU. The inner radius of the disk is predicted to be 31.3 AU, because any closer to the massive protostar, temperatures become high enough for dust grains to sublimate. The total mass of gas in the disk is predicted to be ~12 times the mass of the Sun.
At the center of the Keplerian-like disk lies the still-forming O-type star AFGL 4176. The mass of AFGL 4176 is estimated to be ~25 times the mass of the Sun. Also, AFGL 4176 is predicted to have an effective temperature of roughly 36,900 K and almost 7 times the Sun’s radius. The disk of material around AFGL 4176 is currently the best example of a disk in Keplerian-like rotation around a forming O-type star.
Johnston et al. (2015), “A Keplerian-like disk around the forming O-type star AFGL 4176”, arXiv:1509.08469 [astro-ph.SR]