Accretion properties of T Tauri stars in sigma Ori

Abstract

Accretion disks around young stars evolve in time with time scales of few million years. We present here a study of the accretion properties of a sample of 35 stars in the ~3 million year old star-forming region sigma Ori. Of these, 31 are objects with evidence of disks, based on their IR excess emission. We use near-IR hydrogen recombination lines (Pa_gamma) to measure their mass accretion rate. We find that the accretion rates are significantly lower in sigma Ori than in younger regions, such as rho-Oph, consistently with viscous disk evolution. The He I 1.083 micron line is detected (either in absorption or in emission) in 72% of the stars with disks, providing evidence of accretion-powered activity also in very low accretors, where other accretion indicators dissapear.

Astronomy and Astrophysics, accepted

References in corpus (5)

• Accretion in the Rho-Oph pre-main sequence stars
• Probing T Tauri Accretion and Outflow with 1 Micron Spectroscopy
• High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks
• The brightest stars of the sigma Orionis cluster
• Circumstellar discs in the young sigma Orionis cluster

Cited by in corpus (8)

• Revisiting the pre-main-sequence evolution of stars I. Importance of accretion efficiency and deuterium abundance
• High-Resolution Chandra X-ray Imaging and Spectroscopy of the Sigma Orionis Cluster
• A spectroscopic census in young stellar regions: the Sigma Orionis cluster
• A deep look into the cores of young clusters I. sigma-Orionis
• Stellar parameters and accretion rate of the transition disk star HD 142527 from X-Shooter
• A Herschel view of protoplanetary disks in the $\sigma$ Ori cluster
• Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis
• Testing viscous disc theory using the balance between stellar accretion and external photoevaporation of protoplanetary discs