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.
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- Publication date:
- February 26, 2021
- DOI:
-
- Keyword(s):
- AGB stars Spectroscopy Post main sequence cool stars O-rich Molecules: CO2
- Grants:
-
European Commission:
- NANOCOSMOS - Gas and Dust from the Stars to the Laboratory: Exploring the NanoCosmos (610256)
- Related identifiers:
- Derived from
- 10.1051/0004-6361/202039547 (Journal article)
- https://arxiv.org/abs/2011.01903 (Journal article)
- Communities:
- License (for files):
- Creative Commons Attribution 4.0 International