1. James Owen (IoA, Cambridge) 24-11-2009 Observational Diagnostics of Photoevaporative Winds Around Primordial & Inner Hole Sources James Owen (IoA,Cambridge) Cathie Clarke (IoA,Cambridge) Barbara Ercolano (IoA Cambridge/UCL) Richard Alexander (Leiden/Leicester) Emission From Wind= Blue Shift of a few km/s -6±0.5 km/s -4±2 km/s [NeII] 12.8  m Pascucci & Sterzik (2009) -3±1km/s

2. James Owen (IoA, Cambridge) 24-11-2009 An Example – TW Hya in [NeII] Ercolano, Owen & Clarke 2010, in prep EUV wind model-Massloss Rate 10 -10 M ⊙ /yr X-ray Model- Massloss Rate=10 -8 M ⊙ /yr [NeII] doesn't distinguish between photoevaporation models.

3. James Owen (IoA, Cambridge) 24-11-2009 The [O I] 6300 Problem km/s High Velocity Component Low Velocity Component Hartigan et al. 1995 Low Velocity Component detected with blue shift of a few Km/s and large luminosities of 10 -5 -10 -4 L ⊙ EUV driven photoevaporative wind cannot reproduce this observation and predicts a line luminosity of <10 -6 L ⊙ (Font et al. 2004). Problem: An EUV wind is an ionized wind but [O I] emission requires neutral Oxygen. Solution:The [O I] LVC component must be produced in a partly neutral wind.

4. James Owen (IoA, Cambridge) 24-11-2009 The [O I] 6300 Problem Solved? Radius (cm) Ionization Fraction of Owen et al. (2009) X-ray Driven Photoevaporative Wind Velocity (km/s) Line Luminosity ~10 -4 L ⊙ Ercolano, Owen & Clarke (2010) in prep

5. James Owen (IoA, Cambridge) 24-11-2009 Do We Always Expect to See Blue-Shifted Line Emission No- Close to Edge on Primordial Discs Will Show No Blue Shift. No- Discs With Inner holes are Optically Thin to red-shifted gas Inclination =54 degrees Najita et al. 2009

6. James Owen (IoA, Cambridge) 24-11-2009 Conclusions Have good observational evidence for a slow moving ~ few km/s neutral wind from YSO's. Photoevaporation mostly likely cause. Must have a neutral wind in order to explain observed [O I] line luminosities :- X-ray photoevaporation over EUV photoevaporation? Predicted line profiles from 'Transition Discs' significantly different from primordial discs for X-ray model allow test of source of emission/photoevaporation model. Questions Can we use gas diagnostics to learn about the 'Transition' Phase? Can we use line emmision to distinquish between photoevaporation and planet formation as the cause for a 'transistion' disc? What observational diagnostics can we use to probe the photoevaporation at different radii? What observational diagnostics can we use to probe photoevaporation in 'Transition Discs'?