  The present study makes use of the unprecedented capability of the Gaia
mission to obtain the stellar parameters such as distance, age, and mass of
HAeBe stars. The accuracy of Gaia DR2 astrometry is demonstrated from the
comparison of the Gaia DR2 distances of 131 HAeBe stars with the previously
estimated values from the literature. This is one of the initial studies to
estimate the age and mass of a confirmed sample of HAeBe stars using both the
photometry and distance from the Gaia mission. Mass accretion rates are
calculated from $H\alpha$ line flux measurements of 106 HAeBe stars. Since we
used distances and the stellar masses derived from the Gaia DR2 data in the
calculation of mass accretion rate, our estimates are more accurate than
previous studies. The mass accretion rate is found to decay exponentially with
age, from which we estimated a disk dissipation timescale of $1.9\pm 0.1$ Myr.
Mass accretion rate and stellar mass exhibits a power law relation of the form,
$\dot{M}_{acc}$ $\propto$ $M_{*}^{2.8\pm0.2}$. From the distinct distribution
in the values of the infrared spectral index, $n_{2-4.6}$, we suggest the
possibility of difference in the disk structure between Herbig Be and Herbig Ae
stars.
