The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis

M-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A ^2 Π–X ^2 Σ ^+ band system and can be used to measure the abundance of ScO. In this work,...

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Main Authors: Léo Lavy, Adam Pastorek, Peter F Bernath
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad7af1
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author Léo Lavy
Adam Pastorek
Peter F Bernath
author_facet Léo Lavy
Adam Pastorek
Peter F Bernath
author_sort Léo Lavy
collection DOAJ
description M-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A ^2 Π–X ^2 Σ ^+ band system and can be used to measure the abundance of ScO. In this work, a new Doppler-limited resolution spectrum of ScO obtained in a hollow-cathode experiment is presented. The A ^2 Π–X ^2 Σ ^+ electronic transition is analyzed with special care dedicated to fitting the ${{\rm{A}}}^{{\prime} 2}{\rm{\Delta }}(v+2)$ ∼ A ^2 Π( v ) perturbation. Spectroscopic constants of the A ^2 Π( v ) states are reported for v ≤ 9, and a partial fit of spectroscopic constants is made for the ${{\rm{A}}}^{{\prime} 2}{\rm{\Delta }}(v)$ states 2 ≤ v ≤ 6. The modeled interaction of the two states reproduces the experimental data remarkably well. New equilibrium constants are extracted from the fit. Band strengths are calculated with the help of a scaled transition dipole moment function, previously calculated with ab initio methods. Finally, a line list of the A ^2 Π–X ^2 Σ ^+ band system is provided, including Einstein A coefficients and oscillator strengths. Using this line list, the spectrum of ScO can be simulated for different temperature and pressure conditions in stellar atmospheres.
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spelling doaj-art-fd78bce2d9504d0e866fa6f5bacc0ddf2025-08-20T02:18:39ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01975218010.3847/1538-4357/ad7af1The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral AnalysisLéo Lavy0https://orcid.org/0000-0003-4572-8612Adam Pastorek1https://orcid.org/0000-0001-7935-8571Peter F Bernath2https://orcid.org/0000-0002-1255-396XDepartment of Chemistry and Biochemistry, Old Dominion University , Norfolk, VA 23529, USA ; llavy@odu.eduDepartment of Chemistry and Biochemistry, Old Dominion University , Norfolk, VA 23529, USA ; llavy@odu.eduDepartment of Chemistry and Biochemistry, Old Dominion University , Norfolk, VA 23529, USA ; llavy@odu.edu; Department of Physics, Old Dominion University , Norfolk, VA 23529, USAM-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A ^2 Π–X ^2 Σ ^+ band system and can be used to measure the abundance of ScO. In this work, a new Doppler-limited resolution spectrum of ScO obtained in a hollow-cathode experiment is presented. The A ^2 Π–X ^2 Σ ^+ electronic transition is analyzed with special care dedicated to fitting the ${{\rm{A}}}^{{\prime} 2}{\rm{\Delta }}(v+2)$ ∼ A ^2 Π( v ) perturbation. Spectroscopic constants of the A ^2 Π( v ) states are reported for v ≤ 9, and a partial fit of spectroscopic constants is made for the ${{\rm{A}}}^{{\prime} 2}{\rm{\Delta }}(v)$ states 2 ≤ v ≤ 6. The modeled interaction of the two states reproduces the experimental data remarkably well. New equilibrium constants are extracted from the fit. Band strengths are calculated with the help of a scaled transition dipole moment function, previously calculated with ab initio methods. Finally, a line list of the A ^2 Π–X ^2 Σ ^+ band system is provided, including Einstein A coefficients and oscillator strengths. Using this line list, the spectrum of ScO can be simulated for different temperature and pressure conditions in stellar atmospheres.https://doi.org/10.3847/1538-4357/ad7af1Spectral line listsLaboratory astrophysics
spellingShingle Léo Lavy
Adam Pastorek
Peter F Bernath
The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
The Astrophysical Journal
Spectral line lists
Laboratory astrophysics
title The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
title_full The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
title_fullStr The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
title_full_unstemmed The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
title_short The A2Π–X2Σ+ Band System of ScO for M-type Star Spectral Analysis
title_sort a2π x2σ band system of sco for m type star spectral analysis
topic Spectral line lists
Laboratory astrophysics
url https://doi.org/10.3847/1538-4357/ad7af1
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