Visible Opacities of S-type Stars: The d 3Φ–a 3Δ Band System of ZrO

Abstract

ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d ^3 Φ–a ^3 Δ system ( γ system) with ${v}^{{\prime} }\leqslant 4$ and v ″ ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list can be used to determine Zr abundances in S stars. We also correct the line strengths for the B ^1 Π– A ^1 Δ transition calculated in our previous work.

Keywords

• Rotational spectroscopy
• S stars
• Spectral line lists
• Molecular spectroscopy
• Spectroscopy