Poster Open Access

Detection of infrared fluorescence of carbon dioxide in R Leonis with SOFIA/EXES

J. P. Fonfría; E. J. Montiel; J. Cernicharo; C. N. DeWitt; M. J. Richter

We report on the detection of hot CO2 in the O-rich AGB star R Leo based on high spectral resolution observations in the range 12.8-14.3 µm carried out with the Echelon-cross-Echelle Spectrograph (EXES) mounted on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have found ~240 CO2 emission lines in several vibrational bands. These detections were possible thanks to a favorable Doppler shift that allowed us to avoid contamination by telluric CO2 features. The highest excitation lines involve levels at an energy of ~7000 K. The detected lines are narrow (average deconvolved width ~2.5 km s-1) and weak (usually <10% the continuum). A ro-vibrational diagram shows that there are three different populations, warm, hot, and very hot, with rotational temperatures of ~550, 1150, and 1600 K, respectively. From this diagram, we derive a lower limit for the column density of ~2.2×1016 cm-2. Further calculations based on a model of the R Leo envelope suggest that the total column density can be as large as 7×1017 cm-2 and the abundance with respect to H2 ~2.5×10-5. The detected lines are probably formed due to de-excitation of CO2 molecules from high energy vibrational states, which are essentially populated by the strong R Leo continuum at 2.7 and 4.2 µm.


Files (1.7 MB)
Name Size
1.7 MB Download
All versions This version
Views 4848
Downloads 3535
Data volume 59.7 MB59.7 MB
Unique views 3939
Unique downloads 3232


Cite as