Accretion disks around young stars evolve in time with time scales of a 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 σ Ori. Of these, 31 are objects with evidence of disks, based on their IR excess emission. We use near-IR hydrogen recombination lines (Paγ) to measure their mass accretion rate. We find that the accretion rates are significant lower in σ Ori than in younger regions, such as ρ Oph, consistently with viscous disk evolution. The He I 1.083 μ m line is detected (either in absorption or in emission) in 72% of the stars with disks, also providing evidence of accretion-powered activity in very low accretors, where other accretion indicators disappear.
Gatti T, Natta A, Randich S, Testi L, Sacco G (2008). Accretion properties of T Tauri stars in σ Orionis. ASTRONOMY & ASTROPHYSICS, 481, 423-432 [10.1051/0004-6361:20078971].
Accretion properties of T Tauri stars in σ Orionis
Testi L;
2008
Abstract
Accretion disks around young stars evolve in time with time scales of a 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 σ Ori. Of these, 31 are objects with evidence of disks, based on their IR excess emission. We use near-IR hydrogen recombination lines (Paγ) to measure their mass accretion rate. We find that the accretion rates are significant lower in σ Ori than in younger regions, such as ρ Oph, consistently with viscous disk evolution. The He I 1.083 μ m line is detected (either in absorption or in emission) in 72% of the stars with disks, also providing evidence of accretion-powered activity in very low accretors, where other accretion indicators disappear.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
