John S. Carr et al. 2004 ApJ 603 213 doi:10.1086/381356
John S. Carr1,4, Alan T. Tokunaga2,4 and Joan Najita3,4
Show affiliationsWe report on the detection and analysis of hot rovibrational H2O emission from SVS 13, a young stellar object previously known to have strong CO overtone band head emission. Modeling of the high-resolution infrared spectrum shows that the H2O emission is characterized by temperatures of ~1500 K, significantly lower than the temperatures that characterize the CO band head emission. The widths of the H2O lines are also found to be smaller than those of the CO lines. We construct a disk model of the emission that reproduces the CO and H2O spectrum. In this model, the H2O lines originate at somewhat larger disk radii (≤0.3 AU) than the CO overtone lines (≤0.1 AU). We find that the H2O abundance is about a factor of 10 lower than the calculated chemical equilibrium abundance. Large, approximately transonic, local line broadening is required to fit the profile of the CO band head. If this velocity dispersion is identified with turbulence, it is of significant interest regarding the transport of angular momentum in disks. Large local broadening is also required in modeling CO overtone emission from other young stellar objects, suggesting that large turbulent velocities may be characteristic of the upper atmospheres of the inner disks of young stars.
accretion, accretion disks; circumstellar matter; infrared: stars; planetary systems: protoplanetary disks; stars: formation; stars: pre-main sequence
Issue 1 (2004 March 1)
Received 2003 August 4, accepted for publication 2003 November 13
John S. Carr et al. 2004 ApJ 603 213
N. Drory et al. 2004 ApJ 608 742
N. Cretton et al. 1999 ApJS 124 383