Detection of infrared fluorescence of carbon dioxide in R Leonis with SOFIA/EXES
| Autor: | José Cernicharo, E. J. Montiel, José Pablo Fonfría, Matthew Richter, Curtis DeWitt |
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| Přispěvatelé: | European Commission, National Aeronautics and Space Administration (US), Universities Space Research Association (US), University of Stuttgart |
| Rok vydání: | 2020 |
| Předmět: |
Post main sequence cool stars
Line: identification individual: R Leo [Stars] FOS: Physical sciences Astrophysics Surveys 7. Clean energy 01 natural sciences Stars: individual: R Leo Article symbols.namesake chemistry.chemical_compound 0103 physical sciences Asymptotic giant branch Emission spectrum Spectral resolution identification [Line] 010303 astronomy & astrophysics Spectrograph Spectroscopy Solar and Stellar Astrophysics (astro-ph.SR) Physics 010308 nuclear & particles physics Stratospheric Observatory for Infrared Astronomy Stars: AGB and post-AGB Stars: abundances Astronomy and Astrophysics AGB and post-AGB [Stars] Circumstellar matter 3. Good health Astrophysics - Solar and Stellar Astrophysics chemistry Space and Planetary Science 13. Climate action abundances [Stars] Carbon dioxide O-rich symbols AGB stars Doppler effect Excitation Molecules: CO2 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Astron Astrophys |
| DOI: | 10.48550/arxiv.2011.01903 |
| Popis: | 8 pags., 5 figs., 3 apps. We report on the detection of hot CO2 in the O-rich asymptotic giant branch 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 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 from 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 derived 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 7.0 × 1017 cm-2 and the abundance with respect to H2 ≈ 2.5 × 10-5. The detected lines are probably formed due to the 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. The research leading to these results has received funding support from the European Research Council under the European Union’s Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement n. 610256 NANOCOSMOS. EJM acknowledges financial support for this work through award #06_0144 which was issued by USRA and provided by NASA MJR and EXES observations are supported by NASA cooperative agreement 80NSSC19K1701. Based on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. |
| Databáze: | OpenAIRE |
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