Fourier Transform Spectroscopy of the C3Δ-X3Δ Transition of TiO in Support of Exoplanet Spectroscopy

• Published in: The Astrophysical journal Vol. 863; no. 1
• Main Authors: Hodges, James N., Bernath, Peter F.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10-08-2018; IOP Publishing
• Subjects: astrochemistry; Astrophysics; Correlation; Correlation detection; Extrasolar planets; Fourier transforms; methods: laboratory: molecular; molecular data; Planetary atmospheres; Spectroscopy; Spectrum analysis; Wavelengths
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aacf07

Recent limitations in the TiO line list used in cross-correlation detection schemes have made the detection and quantification of TiO in exoplanetary atmospheres challenging. The quality of the line list appears to degrade at wavelengths shorter than 630 nm. The C -X electronic transition has strong rovibronic bands near 500 nm. In an effort to improve the line list, a spectrum of TiO in a furnace at 1950 K is analyzed, and the assigned lines of the C -X transition are fit with the Hamiltonian in the molecular spectrum fitting software, PGOPHER. Several newly determined molecular constants are reported and the average error in fitting the line positions is 0.017 cm−1 or ∼1 ppm relative error. The new line positions are expected to resolve any problems with cross-correlation templates near 500 nm.