High-Resolution 4.7 Micron Keck/NIRSPEC Spectroscopy of the CO Emission from the Disks Surrounding Herbig Ae Stars

Abstract

We explore the high-resolution (λ/Δλ=25,000 Δv=12 km s-1) M-band (4.7-5.1 μm) spectra of several disk-dominated Herbig Ae (HAe) systems: AB Aur, MWC 758, MWC 480, HD 163296, and VV Ser. All five objects show 12CO v=1-0 emission lines up to J=42, but there is little or no evidence of moderate-J, v=2-1 transitions despite their similar excitation energies. AB Aur shows 13CO emission as well. The line/continuum ratios and intensity profiles are well correlated with inclination, and they trace collisionally driven emission from the inner disk (Rth