We investigate the physical properties of the inner gaseous disks of the three , hot , Herbig B2e stars , HD 76534 , HD 114981 and HD 216629 , by modelling CFHT-ESPaDOns spectra using non-LTE radiative transfer codes .
We assume that the emission lines are produced in a circumstellar disk heated solely by the photospheric radiation from the central star in order to test if the optical and near-IR emission lines can be reproduced without invoking magnetospheric accretion .
The inner gaseous disk density was assumed to follow a simple power-law in the equatorial plane , and we searched for models that could reproduce observed lines of H i ( H \alpha and H \beta ) , He i , Ca ii and Fe ii .
For the three stars , good matches were found for all emission line profiles individually ; however , no density model based on a single power-law was able to reproduce all of the observed emission lines .
Among the single power-law models , the one with the gas density varying as \sim 10 ^ { -10 } ( R _ { * } / R ) ^ { 3 } g cm ^ { -3 } in the equatorial plane of a 25 R _ { * } ( 0.78 AU ) disk did the best overall job of representing the optical emission lines of the three stars .
This model implies a mass for the H \alpha -emitting portion of the inner gaseous disk of \sim 10 ^ { -9 } M _ { * } .
We conclude that the optical emission line spectra of these HBe stars can be qualitatively reproduced by a \approx 1 AU , geometrically thin , circumstellar disk of negligible mass compared to the central star in Keplerian rotation and radiative equilibrium .