1. Gas in Transitional Disks Sean Brittain Clemson University, Clemson, SC, USA Joan Najita National Optical Astronomy Observatory, Tucson, AZ, USA 5 th Planet Formation Workshop

2. Interpretation of the SED

3. Malfait et al. 1998

4. F  F v Gas in Transitional Disks

6. 0.1 AU ~2000 K 10 AU ~500 K 100 AU ~50 K H 2 O ro-vib CO  v=2 CO  v=1 H 2 UV, NIR, MIR OH  v=1 E” J=2 ~500K,  J  1 Freezes at ~170K CO  v=0 FIR [OI], [CI]

7. Kinematic Information From Spectroscopy

8. Malfait et. al. A&A 331: 221 (1998) NIR A0 star “Transitional Disk” Age ~ 6-8 Myr. Regions of interest. A0 star “Classic Disk” Age ~ 4 Myr Clampin, et al. 2003, AJ 126, 385 C. Grady, et al. 2003, ApJ, 683, 151 F /vF v Wavelength (  m)

9. .. HD 141569 AB Aur

10. T=5600 K Blue: Model (R=9-40AU) Red: Data

11. HD 100546: A Transitional Disk Grady et al. 2005 See also Acke et al. 2006 and Bouwman et al. 2003

12. HD 100546 R in (dust)~10AU R in (CO)=7 AU R out (CO)>50 AU

13. Conclusions Need data on gas in disk to properly interpret the SED CO is a robust tracer of warm gas in transitional disks around early HAe and late HBe stars Non-detection of ro-vibrational CO emission can rule out presence of gas within ~50AU