Recent Update of Gas-Phase Chemical Reactions and Molecular Lines of TiO in Cloudy

TL;DR

This paper updates the spectral synthesis code Cloudy with new gas-phase reactions and spectral lines for TiO, enabling more accurate modeling of TiO emission in astrophysical environments like circumstellar regions.

Contribution

It introduces 229 new Ti-related reactions and 66 TiO lines into Cloudy, improving the modeling of TiO in dust-free astrophysical environments.

Findings

Model reproduces observed TiO column density in VY Canis Majoris

Enhanced spectral line predictions for TiO in astrophysical simulations

Improved understanding of TiO formation in gas-phase environments

Abstract

We present our current update on the gas-phase chemical reactions and spectral lines of TiO in the spectral synthesis code Cloudy. For this purpose, we have added 229 Ti-related reactions in the chemical network. In addition, we consider 230 fine-structure energy levels, the corresponding 223 radiative transitions, and 444 collisional transitions with ortho and para H$_2$ and predict 66 TiO lines. We perform spectroscopic simulations of TiO emission from the circumstellar region of the oxygen-rich red supergiant VY Canis Majoris to validate our update. Our model reproduces the observed TiO column density. This update is helpful in modeling dust-free astrophysical environments where Ti is in the gas phase and TiO can form.