The present observational understanding of the evolution of the mass accretion rates (dM/dt_acc_) in pre-main-sequence stars is limited by the lack of accurate measurements of dM/dt_acc_ over homogeneous and large statistical samples of young stars. Such observational effort is needed to properly constrain the theory of star formation and disk evolution. Based on Hubble Space Telescope/WFPC2 observations, we present a study of dM/dt_acc_ for a sample of ~700 sources in the Orion Nebula Cluster, ranging from the hydrogen-burning limit to M*~2M_{sun}. We derive dM/dt_acc from both the U-band excess and the H{alpha} luminosity (L_H{alpha}), after determining empirically both the shape of the typical accretion spectrum across the Balmer jump and the relation between the accretion luminosity (L_acc) and L_H{alpha}, which is L_acc/L_{sun}=(1.31+/-0.03).L_H{alpha}/L{sun}+(2.63+/-0.13). Given our large statistical sample, we are able to accurately investigate relations between dM/dt_acc and the parameters of the central star such as mass and age.

Cone search capability for table J/ApJ/755/154/2cd (Stellar parameters and accretion values of the sources with A_V_ and L_acc_ determined from the 2CD method)

Cone search capability for table J/ApJ/755/154/dario (Stellar parameters and accretion values of the sources with A_V_ from Da Rio+ (Cat. J/ApJ/748/14) and L_acc_ determined from the H{alpha} luminosity)