X-shooter survey Across Regions and Ages to probe Disk Evolution (ARADE). Accretion properties in Orion A and their relation with disk masses

Abstract

We present the largest homogeneous VLT/X-shooter study of accretion in young stellar objects spanning the entire Orion A complex. Our sample includes 91 pre-main-sequence stars hosting a protoplanetary disk according to photometry, selected to span a wide range of optical colors, 34 of which have complementary ALMA dust mass measurements. Spitzer We derived the stellar and accretion properties using a self-consistent multicomponent fitting procedure. Our sample encompasses spectral types from K3 down to M5, corresponding to stellar masses within ∼0.8-0.1 The accretion-stellar luminosity ( and the scaling relations of the mass-accretion rate to stellar mass ( in Orion A are consistent with those of other star-forming regions that span a range of stellar densities, far-ultraviolet (FUV) irradiation fields, and ages, with all regions occupying the same locus in parameter space. For the 34 sources with complementary dust mass measurements, we present the first investigation of the and disk mass ( = correlation in Orion A, recovering a spread consistent with that reported for other regions. Although our sample spans nearly five orders of magnitude in local FUV field strength, we found no statistically significant correlation between and FUV irradiation. However, by combining our sample with literature measurements in Lupus, the Orion nebula cluster, and σ Orionis, we found a tentative population-level decrease in the inferred disk lifetime t_ ̊m disk toward stronger FUV environments, but the large intrinsic scatter and limited sample sizes at intermediate- and high-FUV fields prevent firm conclusions. The homogeneous measurements reported here provide a solid foundation for future studies of accretion and disk evolution in the diverse environments of Orion A and other star-forming regions.