Document Type
Article
Publication Date
2025
DOI
10.3847/1538-4357/ad9c7a
Publication Title
The Astrophysical Journal
Volume
979
Issue
1
Pages
19 (1-12)
Abstract
The spectral analysis of molecule-rich asymptotic giant branch (AGB) stars is challenging. Although other calcium and fluorine bearing molecules are observed in the microwave and in the visible spectrum of AGB stars, CaF has never been detected, despite favorable chemical equilibrium predictions. Yet, measuring the CaF abundance could give more insight into the fluorine budget of AGB stars and allow better simulation of stellar spectra. In this work, we present an analysis of the visible spectrum of CaF obtained with a Fourier transform spectrometer. CaF A²Π−X²Σ⁺ and B²Σ⁺−X²Σ⁺ band systems were excited with a hollow cathode discharge. Using previous fluorescence spectroscopy measurements, highly accurate ground state constants, and reasonable extrapolation schemes, the strongest features of CaF in the visible spectrum can be accurately modeled for both band systems. Spectroscopic constants are determined for A² Π with v ≤ 16 and for B²Σ⁺ with v ≤ 20. Ab initio transition dipole moment curves of both transitions were calculated and scaled, and we provide a line list with Einstein A coefficients and oscillator strengths. This line list can be used to simulate spectra of CaF at temperatures and pressures relevant to astrophysical environments.
Rights
© 2025 The Authors.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Data Availability
Article states: "The tabular data (Tables 1, 2, 6) created for this work is provided in the machine-readable format in the online Journal article. The PGOPHER (Version 10.1.182) configuration file, containing the published spectroscopic constants and band strengths, is available on Zenodo doi:10.5281/zenodo.14080064."
Original Publication Citation
Lavy, L., Bernath, P. F., & Pastorek, A. (2025). Line list for the A²Π−X²Σ⁺ and the B²Σ⁺−X²Σ⁺ band systems of CaF. The Astrophysical Journal, 979(1), 1-12, Article 19. https://doi.org/10.3847/1538-4357/ad9c7a
ORCID
0000-0003-4572-8612 (Lavy), 0000-0002-1255-396X (Bernath), 0000-0001-7935-8571 (Pastorek)
Repository Citation
Lavy, Léo; Bernath, Peter F.; and Pastorek, Adam, "Line List for the A²Π−X²Σ⁺ and the B²Σ⁺−X²Σ⁺ Band Systems of CaF" (2025). Chemistry & Biochemistry Faculty Publications. 342.
https://digitalcommons.odu.edu/chemistry_fac_pubs/342