Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 2S039

Understanding the origin of the [OI] low-velocity component from young stars

Rigliaco, Elisabetta (University of Arizona)
Pascucci, Ilaria (University of Arizona)
Gorti, Uma (SETI Institute)
Edwards, Suzan (Astronomy Department Smith College)
Hollenbach, David (SETI Institute)

Accretion of matter onto the central star, protostellar winds/jest, disk winds, photoevaporative winds operate concurrently in dispersing protoplanetary disks. Disentangling their relative contribution requires identifying diagnostics that trace different star-disk environment. Here we analyze the low-velocity component (LVC) of the [O I] 6300A, 5577A lines. We compare these lines to the LVC of the [Ne II] 12.81μm (which has been found to trace photoevaporative disk winds driven by stellar X-ray/EUV photons) and to the narrow component (NC) of the CO fundamental band at 4.7μm (which has been proposed as disk wind tracer). We find that these three diagnostics may arise from different regions around the star. We find that the luminosity of the [O I] LVC is proportional to the stellar FUV luminosity, and we show that the [OI] 6300A/5577A line ratio is low. These findings favor an origin of the [OI] LVC in a region where OH is photodissociated by stellar FUV photons. A detailed modeling of the highest resolution spectra reveals multiple components within the [OI] LVC, with one component likely tracing a photoevaporative wind either driven by stellar FUV and/or X-ray photons.

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