1 / 6

James Owen (IoA, Cambridge) 24-11-2009

Observational Diagnostics of Photoevaporative Winds Around Primordial & Inner Hole Sources. -3 ±1 km/s. -6 ±0.5 km/s. James Owen (IoA,Cambridge) Cathie Clarke (IoA,Cambridge) Barbara Ercolano (IoA Cambridge/UCL) Richard Alexander (Leiden/Leicester).

lecea
Download Presentation

James Owen (IoA, Cambridge) 24-11-2009

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Observational Diagnostics of Photoevaporative Winds Around Primordial & Inner Hole Sources -3±1km/s -6±0.5 km/s 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 -4±2 km/s [NeII] 12.8m Pascucci & Sterzik (2009) James Owen (IoA, Cambridge) 24-11-2009

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

  3. The [O I] 6300 Problem 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 <10-6L ⊙ (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. High Velocity Component Low Velocity Component km/s Hartigan et al. 1995 James Owen (IoA, Cambridge) 24-11-2009

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

  5. 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 James Owen (IoA, Cambridge) 24-11-2009

  6. 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'? James Owen (IoA, Cambridge) 24-11-2009

More Related