Document Type

Article

Publication Date

2024

DOI

10.3847/1538-4357/ad499e

Publication Title

The Astrophysical Journal

Volume

970

Issue

1

Pages

13 (1-12)

Abstract

Cool red giant stars exhibit absorption bands of calcium monochloride (CaCl) in the optical region. In this work, the bands of CaCl corresponding to the A2Π − X2Σ+ transition with v′ ≤ 4 and v″ ≤ 4, and B2Σ+ − X2Σ+ transition with v′≤ 2 and v″ ≤ 2 are rotationally analyzed with PGOPHER, a multipurpose program for simulating and fitting molecular spectra. All bands were analyzed using high-resolution absorption spectra collected at the National Solar Observatory in 1985, calibrated with atomic lines from a high-resolution emission spectrum obtained in a separate hollow cathode experiment. The results are compared with previous laser-induced fluorescence measurements. Overall, the accuracy of spectroscopic constants for the A2Π and B2Σ+ states is improved. Scaled transition dipole moment calculations were used to obtain line strengths. Line lists are provided with Einstein A coefficients and oscillator strengths, which can be used to determine CaCl stellar abundances. Additionally, isotope splittings allowed us to estimate band origins for the 40Ca37Cl isotopologue based on band-head positions.

Rights

© 2024. The Authors

Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 License (CC BY 4.0). Any further distribution of this work must maintain attribution to the authors and the title of the work, journal citation, and DOI.

Comments

Unified Astronomy Thesaurus Concepts:

Special line lists

Laboratory Astrophysics

Original Publication Citation

Lavy, L. & Bernath, P. F. (2024) Molecules in cool stars: The A²Π - X²Σ⁺ and the B²Σ⁺ and the B²Σ⁺ - X²Σ⁺ band systems of CaCl. The Astrophysical Journal, 970(1) 1-12, Article 13. https://doi.org/10.3847/1538-4357/ad499e

ORCID

0000-0003-4572-8612 (Lavy), 0000-0002-1255-396X (Bernath)

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