Oscillator Strengths and Predissociation Rates for Rydberg Complexes in 12 C 16 O between 92.9 and 93.4 nm M. Eidelsberg, J.L. Lemaire (Obs. de Paris), S.R. Federman (U. of Toledo), G. Stark, A.N. Heays (Wellesley), L. Gavilan (Obs. de Paris), J.-H. Fillion (UMPC), F. Rostas, (Obs. de Paris), J.R. Lyons (UCLA), P.L. Smith (Wellesley), N. de Oliveira, D. Joyeux, M. Roudjane, and L. Nahon (SOLEIL) This research was supported by grants from NASA and CNRS-PCMI program

Outline Background Previous Work on CO Photochemistry New Results from SOLEIL Summary

Background CO observed in many astronomical environments –Diffuse and dark, molecular interstellar clouds –Circumstellar shells of asymptotic giant branch stars and planetary nebulae –Circumstellar disks around newly formed stars –Comets and planetary atmospheres Experimental data for photochemical models –Electronic transitions (ultraviolet) –Oscillator strengths –Predissociation rates

Our Previous Work on CO Photochemistry FUSE Observations (Sheffer et al. 2003, ApJ, 597, L29) Consistent with results of Federman et al. (2001, ApJS, 134, 133) Confirmed by Eidelsberg et al. (2004, A&A, 424, 355) Confirmed by Eidelsberg et al. (2006, ApJ, 647, 1543) and Eidelsberg et al. (2012, A&A, in press) for W1, W2, and W3

SOLEIL Experiments DESIRS beamline with a VUV FTS at SOLEIL Synchrotron

SOLEIL Experiments The FTS (de Oliveira et al. 2009, Rev. Sci. Instru., 80, ; de Oliveira et al. 2011, Nature Photonics, 5, 149) –Resolving power as high as 750,000 –Based on wave front division instead of amplitude division –Relies on modified bimirror configuration requiring only flat mirrors –Path difference scanning through translation of one reflector

SOLEIL Experiments Need calibration band: use B – X (0,0)

SOLEIL Experiments Typical bandpass

SOLEIL Experiments Synthesis of Rydberg complexes

SOLEIL Experiments Model for Rydberg complexes

SOLEIL Experiments Results for Rydberg Complexes in 12 C 16 O

Summary VUV FTS allows us to extract data on individual bands, including predissociation rates Summed oscillator strengths for region consistent with previous results Detected continuum whose origin is not known Extending analyses to bands in rarer isotopologues – 13 C 16 O, 12 C 18 O, and 12 C 17 O

A New Division within the AAS The Laboratory Astrophysics Division: Brings users and providers together Membership questions: