Séminaire

Mardi 7 Novembre 2023 à 11h00.

The iron hydride molecule, FeH: new spectroscopy and new astrophysical implications

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Despite its simple structure, FeH has a very complex spectrum. The complexity is due to the high spin and orbital angular momentum of most of its electronic states, which leads to a high density of states overall. Understanding the FeH spectrum is of great importance, since it is present in the atmospheres of cooler stars, and in the atmosphere above sunspots on our sun. FeH is also used as a sensitive probe of stellar velocities, and subtle Doppler shifts its spectrum can be used to detect the presence of exoplanets orbiting M- and L-class stars.

Most of our present understanding of FeH came from extensive laboratory work undertaken between 1988-2006 by Dr. J. M. Brown (Oxford U.). In this talk I will discuss recent experiments undertaken by our group at the University of New Brunswick in collaboration with colleagues at Université Lyon 1. We have identified new electronic states in this molecule, and have explored the Zeeman response of selected states by applying strong magnetic fields to it. Our techniques for creating and observing it, which include laser excitation spectroscopy, Fourier transform spectroscopy of the laser-induced emission, and wavelength-selective detection, will be described. The implications of our work for exoplanet detection, particularly by the new velocimeter SPIRou on the Canada-France-Hawaii

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