A hybrid approach to generating diatomic line lists for high resolution studies of exoplanets and other hot astronomical objects: Updates to ExoMol MgO, TiO and VO line lists

TL;DR

This paper enhances molecular line lists for exoplanet and hot astronomical object studies by integrating empirical and predicted data to improve accuracy and completeness, updating key isotopologue line lists for better spectroscopic analysis.

Contribution

It introduces methods to extend empirical energy levels using predicted shifts and isotopologue extrapolation, updating the ExoMol line lists for multiple isotopologues with improved accuracy.

Findings

Updated line lists for MgO, TiO, VO isotopologues with enhanced accuracy.

Incorporated Marvel results for 51V16O.

Improved spectral completeness for high-temperature astrophysical modeling.

Abstract

The best molecular line lists for astrophysical applications today require both high accuracy of line positions for strong lines as well as high overall completeness. The former is required to enable, for example, molecular detection in high-resolution cross-correlation observations of exoplanets, while completeness is required for accurate spectroscopic and radiative properties over broad temperature and spectral ranges. The use of empirical energies generated with the Marvel procedure is a standard way to improve accuracy; here we explore methods of extending the use of these levels using predicted shifts and isotopologue extrapolation, as well augmenting the levels from other sources such as effective Hamiltonian studies. These methods are used to update ExoMol line lists for the main 24Mg16O and 48Ti16O isotopologues, as well as for 24Mg17O, 24Mg18O, 25Mg16O, 26Mg16O, 46Ti16O, 47Ti16O, 49Ti16O and 50Ti16O; new Marvel results for 51V16O are also presented