Contributed Talk - Splinter SOFIA

Tuesday, 12 September 2023, 14:50   (H 3006)

The envelopes of Late-type stars seen in the infrared at high spectral resolution

G.W. Fuchs1, E. Döring1, and T.F. Giesen1, and T.K. Greathouse2, R.S. Giles2, and J.H. Lacy3 and E.J. Montiel4 and M.J. Richter5
1) University of Kassel, Institute of Physics, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; 2) Space Science Department, Southwest Research Institute, San Antonio, TX, USA; 3) Department of Astronomy, The University of Texas at Austin, Austin, TX, USA; 4) USRA, NASA Ames Research Center, Moffett Field, CA, USA; 5) Department of Physics, University of California, Davis, Davis, USA

Our universe is full of molecules. Most molecules have been discovered with the help of radio or MM telescopes based on their rotational spectra in the interstellar medium or in circumstellar envelopes around old stars. But molecules can also be detected unambiguously in the infrared (IR) range, and even those that do not have a permanent electric dipole moment. Once IR high-resolution laboratory spectra are available, they can be used to identify molecules from astrophysical observational data provided that these are also available at high spectral resolution. The molecular envelopes around aging stars provide an excellent opportunity to study molecular species and also the dynamics of their environment like the outflows, shock waves, the expansion of molecular shells or the infall of material into a star. For this purpose, own observations were made with the SOFIA aircraft telescope and at the IRTF telescope on Mauna Kea, Hawaii on selected astronomical objects. Example IR spectra from hypergiant stars such as VY CMa (EXES & TEXES observations) and NML Cyg, as well as observations of variable AGB stars such as Mira (o Cet), Chi Cyg, IK Tau, and R Cas will be presented. With the help of the high-resolution spectra, molecular abundances, ambient temperatures, and dynamical processes can be determined. This will be demonstrated on the molecule silicon monoxide (SiO) and others.